Dagur the Deranged is a former villain and archenemy-turned-ally of Hiccup and the Dragon Riders in the DreamWorks Dragons TV Series, and the Chief of the Berserker Tribe. Later, in Race to the Edge, he proves himself changed and does everything he can to help the Dragon Riders, which includes seemingly sacrificing himself to prevent them from taking on a suicide mission.
- "Dagur is obsessed with Dragons and hates Hiccup.
After his defeat, Dagur the Deranged was imprisoned on Outcast Island for three years. But rather than rehabilitate his fractured mind, Dagur instead focused solely on his next attack on the Dragon Riders. Dagur packed on considerable muscle during his time in jail, making him an even more formidable fighter. He finally escaped from his cell and the archipelago, eventually finding a new fleet of ships. With a new armada now under his control, Dagur is ready to launch his final assault on Hiccup and Toothless, and he's going to use the mysterious Dragon Eye to do it."
- ―Viking Guide 
Dagur first appears in "Twinsanity", when the Hooligan Tribe is expecting an annual visit from the chief of the Berserkers, Oswald the Agreeable. But then when the Berserker ships arrive at the island, it is shown that Oswald the Agreeable's son, Dagur, has become the new chief of the Berserkers, and now has the title of Dagur the Deranged.
The visit to Berk is to renew a peace treaty between the Berserkers and the Hooligans. Dagur spends most of the time insulting his father and looking for dragons to kill, ignoring the polite demeanor of Stoick and the other Vikings. Later in the episode, when Barf and Belch burst into the Great Hall, he leads the Berserkers in a hunt to catch the rogue Zippleback. Barf and Belch are brought into the arena so that Dagur and Stoick can kill them and sign the treaty in dragon's blood (which Dagur has continually requested). However, the execution is stopped by an "attack" staged by the other dragons, directed by their riders with hand signals. Dagur is forced to flee, telling Gobber the Belch to consider the treaty signed.
Though the Dragon Riders try their best to hide their dragons and the fact that Berk actually trains them, Hiccup is forced to reveal the secret in order to save Toothless in "The Night and the Fury". This enrages Dagur, who sees this as a violation of the peace treaty. However, despite his advantage of strength and rage, Dagur is defeated by Hiccup's tactics, shield, and Toothless. He later swears revenge, but orders his men not to touch Hiccup, stating that he is going to take care of it himself.
In "A View to a Skrill, Parts 1 and 2", Dagur and his Berserkers then fought Hiccup and the Dragon Riders over a freshly-revived Skrill. Dagur's tribe later joins forces with Alvin the Treacherous and the Outcast Tribe in order to attack Berk. Dagur double-crosses Alvin, apparently killing him and forcing the remaining Outcasts to swear loyalty to him. However, Dagur loses the Skrill to Hiccup and is now even more determined to destroy him and capture Toothless.
He gained full control over the Outcasts and their Island, merging his army with theirs and increasing his military might so that his forces will be strong enough to attack Berk.
Meanwhile, the dragon riders come across Outcast Island and discover that the Berserkers are building something, but they cannot find out what it is. Thinking that it is nothing important, the teens leave the island and head for home. Later, Trader Johann returns from Outcast Island and informs Stoick that he overheard the Berserkers talking about a new weapon. Stoick relays the information to Hiccup and assumes that this weapon is what the riders saw on Outcast island.
When the dragon riders return to Outcast Island in "The Flight Stuff", they discover that the new weapon is a large catapult that fires nets to capture dragons. The Berserkers successfully use it to bring down Gustav and Fanghook, as well as Hiccup and Toothless. When Toothless is captured, Dagur attempts to kill him and Hiccup but his plans are foiled by Snotlout and Gustav and their dragons. The dragon riders leave Outcast island, and Dagur questions why his plans never seem to work. Savage suggests that it is because of Dagur's execution, to which Dagur agrees and threateningly pulls out his sword while the men cower.
During the events of "Smoke Gets in Your Eyes", Dagur then uses strategy in his attack by tricking Trader Johann into bringing a load of scrap metal to sell to Berk. However, Johann is unaware that the scrap pile is actually a Smothering Smokebreath nest, filled with hatchlings. Throughout the course of two days, the Smokebreaths steal all of Berk's metal, including weapons, leaving island vulnerable to attack. Dagur sends the Berserker armada to Berk intending to destroy the island settlement (and make Hiccup kiss his boots). However the dragon riders have learned that they can control the Smokebreaths and ruin Dagur's plans by having the Smokebreaths steal the metal that holds the ships together. The Smokebreaths do so, and the ships literally fall apart under the Berserkers' feet, leaving Dagur and Savage floating on a wooden raft. Dagur pushes Savage off into the water and declares that it is not over, before having his helmet stolen by a Smokebreath. He mutters to Hiccup, "You will kiss this boot..." and floats away.
As shown in "Cast Out, Parts 1 and 2", Dagur returns with plans to capture Hiccup and the dragon riders. Together with his armada, he sneaks onto Berk and plants a dragon root in the academy. When the dragon riders (except Hiccup) try to remove the dragon root and calm their dragons down, Dagur locks them in the academy, forcing Hiccup to surrender Toothless in exchange for his friends' freedom. However, Stoick and the villagers intervene, leading to a major brawl between the Berserkers and Hooligans. During the battle, Alvin intervenes, much to Dagur's surprise. When they run out of luck, Savage suggests retreating, but Dagur, refusing to leave Berk empty-handed, captures Stoick as hostage in exchange for Toothless. He is last seen loading Stoick onto his ship.
He then had Savage deliver a message to Berk, stating that he will trade Stoick for Toothless, and that Hiccup has twenty-four hours to respond. Hiccup decides to work with Alvin, who knows the layout of Outcast Island better than anyone. The two manage to sneak past the islands' defenses, but are captured in the arena. Dagur, however, captures Toothless and imprisons Hiccup , deciding to make the Night Fury the new symbol of the Berserkers, which would involve many changes. He suggests renaming Toothless "Deathkiller," as the former name doesn't make any sense to the Berkserker chief (Toothless is always bearing his teeth at Dagur). When Alvin and Mildew release the Whispering Deaths, the Outcast Arena collapses, causing Dagur, his soldiers and Toothless to fall into the pit below. Dagur tries to get on the dragon's back, but is quickly thrown off. However, when the Screaming Death shows up, Dagur realizes why the dragon is so upset and captures its mother. Thankfully, Snotlout shows up and frees her, allowing the Whispering and Screaming Death dragons to fly off with one another, reunited. After the battle, Dagur tries to attack, but is stopped by Alvin. He is last seen being threatened and calling out to Hiccup and it is likely that Alvin took back leadership over all of the Outcasts.
Dagur returns in Race to the Edge and serves as the main, later tertiary antagonist. As shown in Dragon Eye of the Beholder, Part 1, about three years after his defeat by the Hairy Hooligans, the Outcasts, and the dragons, Dagur was imprisoned by Alvin, and is no longer chief of the Berserker tribe. Vorg and a few others Berserkers, including Savage, were imprisoned as well due to their loyalty. He eventually escaped and stole Johann's ship. He planned to steal the gold from Trader Johann to rebuild his army. He soon crosses paths with Hiccup and the Dragon Riders, with the former discovering the Dragon Eye. Dagur initially takes it from Hiccup, but the young Viking quickly manages to steal it back. Dagur still manages to get away with Johann's treasure.
In "Gone Gustav Gone", Dagur's men manage to salvage the traps from The Reaper, but Dagur is still after the Dragon Eye. Later, they capture Gustav Larson, who agrees to help Dagur get it by having Hiccup trade for Gustav. The unofficial dragon rider takes Dagur to an island using the Dragon Eye, to get the treasure. However, this was a trick, with Hiccup's help to get the Dragon Eye back. Dagur, realizing he's trapped, drops the Dragon Eye into a chasm, distracting Hiccup. Dagur manages to escape, but luckily Gustav and Hiccup are able to get the Dragon Eye back.
It was revealed in "Have Dragon Will Travel, Part 2", that before his imprisonment on Outcast Island, that Dagur wiped out Heather's village and her family. In a rage, she tried to kill him. Dagur immediately recognized Heather and proceed to capture her, but she and her dragon Windshear were saved by Hiccup. Dagur later planned to meet with another tribe to rig his ship with dragon proof catapults and winches, though the Dragon Riders were tipped off by Johann and set out to capture him. While Fishlegs, Snotlout, and the twins distracted Dagur, Heather and Astrid snuck aboard to take out his men. When defeated, Heather commanded Windshear to kill Dagur to avenge her family, only to be stopped by Hiccup and Toothless. Hiccup explained to Heather that her horn, which her father gave to her, was a gift from Stoick to Oswald the Agreeable for his newborn daughter. This meant that Dagur was actually Heather's brother. He attempted to ask her to join him, but to no avail. He was left calling after Heather as she flew away from his ship.
Dagur then attacked Berk to lure the Dragon Riders out in "Team Astrid", then following them to find Dragon's Edge. In the process, however, he destroyed Astrid's home which inspired her to train an auxiliary team to protect Berk. The new riders assisted in defending Dragon's Edge from Dagur, forcing him to retreat.
During the events of "Night of the Hunters, Parts 1 and 2", Dagur is revealed to have joined Ryker and the Dragon Hunters, and Heather has joined him as well. Ryker, Heather, and Dagur try to get Astrid to tell them where the Dragon Eye was. Dagur tried to convince Ryker to throw the riders overboard, but Heather suggests they use them as slaves for Viggo. Dagur confronts his sister for opposing his idea, to which she replies that she was protecting him. That if something went wrong, Ryker would be blamed and not Dagur. Hiccup and Snotlout soon arrive and manage to free the other riders.
Dagur and Ryker later appeared in "The Zippleback Experience", when they planned to kidnap Hiccup and use him find the islands the Dragon Eye had led the riders to. Once they had Hiccup, they began to sail out. However, Barf & Belch witnessed Hiccup's abduction and set out to rescue him. They also sent out their distress signal to call the other riders. Dagur was about to fire multiple arrows using a large crossbow, but was blown up by the Zippleback. The hunters managed to capture Barf & Belch, but were saved by Ruffnut and Tuffnut. The Dragon Riders continued to attack the ship, forcing the hunters to retreat.
Dagur was then sent on a wild goose chase by Heather to find a second Dragon Eye as mentioned during the events of "Snow Way Out".
Dagur, alongside Heather, Ryker and their fleet, then attacked Dragon's Edge in "Edge of Disaster, Parts 1 and 2". After having his men kidnap Ruffnut, Dagur then questioned her about the Edge's defense. Despite Ruffnut's false claims, Dagur continued to try to get in Dragon's Edge to steal the Dragon Eye. After several failed attempts, Dagur realized he hadn't seen Hiccup, Snotlout, Fishlegs, or their dragons. This meant they did fall for the Hunters trick by luring Johann to an island that was home to dragon that had been attacked by the Hunters, and split up. Dagur faced off against Astrid, but was quickly overpowered by her. Hiccup and the other Riders soon arrived, along with the herd of wild dragons to protect the Edge. Dagur managed to escape with Heather and the Hunters.
During one of their runs in "A Time to Skrill", the Dragon Hunters spotted a storm, which Dagur immediately recognized as the Frozen Skrill from three years earlier. Determined to get it back, Dagur tells the Hunters to head towards the flashes. He was surprised that Hiccup actually brought the Skrill to them, but returned his attention back to capturing it. After taking the Skrill down with the Dragon Root arrows, Hiccup tries to grab the dragon away, but is cut off, thus returning the Skrill back into Dagur's hands. The Dragon Hunters later landed on an island to rest, while placing the Skrill in water so he couldn't shoot lightning. Knowing Hiccup would come back for the dragon, Dagur and Ryker soon captured the Dragon Riders as well. However, Hiccup manages to get to Toothless, who in turn frees the Skrill. Once free, the Skrill attacks Dagur and the Dragon Hunters, forcing them to run.
After another failed fight against the Dragon Riders in "Maces and Talons, Parts 1 and 2", Ryker begins to suspect Heather is giving them information. However, Dagur defends his sister and threatens Ryker if he tries to hurt her. Ryker is soon given information that it time to meet up with Viggo. Heather asks Dagur what he knows of the Dragon Hunters' leader. He describes him as being the opposite of Ryker, svelte and smart, even more so than himself, which he doesn't quite believe; and that he loves the art of the kill. Dagur also tells Heather that Ryker is even afraid of Viggo, despite being the older brother. Dagur soon drops the subject and hugs Heather, happy that the two of them are together after so many years. Dagur joins Ryker and the Dragon Hunters in capturing a Flightmare.
When it is revealed Heather is a traitor, Dagur is tasked with locking her up. Heather tries to reason with her brother that they should not turn on each other. This causes Dagur to viciously question Heather about her family values when she had tried to kill him before. Heather reminded him that she didn't know he was her brother at the time, and that he had destroyed her island. Seeing Heather's point, he asked if she was still mad about that. When she doesn't respond, Dagur locks her up, telling her that the only one he can trust is himself. Later on, Dagur plays Maces & Talons with Viggo, using their men. While Dagur gains the upper hand, Viggo still beats him, showing his readiness to make sacrifices. After the Dragon Riders begin their attack, Viggo sends Dagur off to take care of Heather. Before he does, Dagur asks Ryker why he puts up Viggo. The hunter replies that even though Viggo gets to him, he's still his brother, leaving Dagur alone to think. Dagur and two Hunters later take Heather away. However, the two men notice something is off, just before Dagur bashes their heads together, knocking them out. He takes out his axe and uses it to free Heather from her shackles, and whistles for Windshear. Dagur then leaves, but not before looking back at his sister.
Eventually, after Heather's reveal and explains her disappearance, Dagur goes looking for his sister and finds himself on an island alone where he thinks and begins changing allegiance. When Hiccup and Toothless get hit by the Dragon Hunter's dragon root arrows in "Enemy of My Enemy", they crash land on the same island. Hiccup hides Toothless in a cave and goes out to draw the Hunters away and buy the duo a little time. As he does so, Dagur ambushes the Dragon Hunters one by one until he finally reveals himself to be Hiccup and Toothless' savior. Hiccup doesn't believe what he says and even attacks Dagur in an attempt to protect Toothless. It takes a lot of convincing from the former Berserker chief to gain enough trust to lead Hiccup into a safe cave near a waterfall. As they go Hiccup is still unsure of Dagur's newfound allegiance and gets nervous when Dagur pulls out a knife and throws it past his head. It is only when the knife unsets a dragon trap that he calms down, but only slightly. On the trail there, it is very slippery and Hiccup and Dagur both almost fall into the waters below. Dagur apologizes for his lack of thought to warn Hiccup of the danger beforehand. Once in the cave Dagur takes the liberty of making Toothless as comfortable as possible, giving him a pillow, as he explains to Hiccup why he was helping him out. He even tells Hiccup of the antidote to cure the symptoms of the dragon root arrows. He throws Hiccup a sword before they go out in search of the ingredients.
As they gather the needed items, they come across a camouflaged Changewing and Dagur whistles into his hands as it begins an attack. The dragon immediately calms down and leaves. They soon come to a large rock that has the final ingredient on the top, a purple oleander. Hiccup climbs up as the Dragon Hunters prepare an ambush. Dagur easily takes them out and holds a mace above a knocked out Hunter before dropping it to the ground as evidence of his change. Once Hiccup makes it down he pushes him out of the way of an arrow, getting hit himself. Hiccup takes Dagur back to the cave and even gives him a sling to hold his arm. Once the antidote is finished Hiccup gives it to Toothless. Not a moment later, the dragon is in a fit of spasms and roars before dropping to the ground. Hiccup blames Dagur for hurting his dragon and pushes both of them out of the cave and into a river. Once they reach the shore, the Dragon Hunters have them surrounded and held them captive for information on the whereabouts of Toothless. When a Hunter threatens to brand Hiccup, Dagur makes an escape attempt but leaves Hiccup behind. Once gone, Dagur pauses for a moment, but continues towards the cave where Toothless is hiding. Before anything bad can happen to Hiccup, Toothless attacks the Hunters, with the help of Dagur riding on his back. Once defeated Dagur reunites Hiccup and Toothless, cuts Hiccups ropes, and they part ways.
During the events of "To Heather or Not to Heather", Dagur sends a letter to the Riders asking for help to find his sister, unaware that Heather is with them. They decide to keep her location a secret from Dagur.
Dagur soon finds his way to Dragon's Edge in "Family on the Edge", and surprises Hiccup in his hut. Dagur pleas with Hiccup to teach him how to ride dragons so he can find Heather. Hiccup finally agrees, telling Dagur to camp out on the far side of the island, as well as try to keep Heather, and the others, from knowing her brother is there. The next morning, Hiccup introduces Dagur to his dragon, Shattermaster, a green Gronckle. He begins training him to ride until Dagur and his dragon crash on top of Hiccup and Toothless, ruining his leg. Hiccup takes Shattermaster to his hut to get a spare, leaving Toothless with Dagur, who decides to ride on Toothless to pass the time. He crashes and is surrounded by Astrid, Fishlegs and Ruffnut and Tuffnut. They surround him thinking he had hurt Hiccup until the young Viking shows up on the scene explaining what had happened. Eventually the gang trusts Dagur enough, each taking a turn teaching him how to ride showing him new tricks and improving his bond with Shattermaster. When Snotlout and Heather come back from checking out their target for their next attack, Heather attacks Dagur with a punch and blames Hiccup for helping her mortal enemy. Dagur eventually walks out on the verge of tears until he comes across the gang's battle plan. He tells them it was a trap before they lock him in a cell. They saddle up the next day seeing Dagur has been broken out by his dragon. They follow on his trail and watch as he is attacked by dragon hunters. They become fully aware that it was indeed a trap. Dagur continues to attack the hunters despite the impossible odds. He takes out two knives and flies into an enormous cloud of smoke as the music swells heroically. Hiccup tries to rally the riders to go and help him, but Astrid stops him. She tells him that Dagur is gone, and that there is nothing they can do. Before he left, Dagur left a note for Heather saying he didn't want Hiccup leading her into a trap, he never killed their father, and that he was sorry for everything he had done. Dagur was changed by his sister, and was a hero till the very end, even if the time he spent redeemed was short lived and no one trusted him.
Dagur is revealed to have survived in Saving Shattermaster. Hiccup and Heather encounter him on a trading post where he seems to have aligned himself with the Dragon Hunters again. When Hiccup and Heather first confront him, he claims to not know who they are. Hiccup and Heather decide to kidnap him and take him back to the Edge. When they grab him, Dagur admits that he was faking the amnesia because he was working undercover with the Dragon Hunters in attempt to save his dragon, Shattermaster. Hiccup and Heather help him infiltrate the ship carrying the Gronckles and save Shattermaster. Dagur and Shattermaster then lead the Dragon Hunters away, so that Hiccup and Heather can escape.
Dagur returns to the Edge in Gold Rush. He informs the Riders that he learned from a Hunter where Viggo hides his gold. In exchange for his help in stealing the gold, he asks for portion of the gold so that Heather and him can find their father and restore the Berserker Tribe. Heather initially wants nothing to do with Dagur; however, after spending time with him while on the mission, she starts to learn what it truly means to be a Berserker and grows closer to her brother. After they successfully steal Viggo's gold, Heather agrees to go with Dagur.
Dagur and Heather return in Shell Shocked, Part 1 and Shell Shocked, Part 2. It is revealed that Dagur and Heather have resettled Berserker Island; however, it is soon attacked by Ryker and the Shell Fire. They are forced to evacuate the island to save their people. Dagur later helps the Riders defend the Edge from the Hunters. After Shattermaster gets hurt, Dagur resigns himself to die fighting; however Sleuther defends him and allows him to ride him. He is last seen riding Sleuther, who is carrying Shattermaster, to get treated for his injuries.
Dagur has red hair and dark green eyes. He is rather skinny for a Viking, probably because he is young. He has been shown to tower over most of the teens in Berk nonetheless. He has two tattoos of three lines like claw marks, one across his left eye and the other on his upper right arm.
In the first two seasons, Dagur's hair is pulled back in a braid, with a helmet that covers most of his head, and long horns on it. Under it he wears a black headband. He has a brown shirt and a tan and green tunic with metal studs. His left arm is covered in green bindings, with a large one on his forearm and a spiky elbow pad, and his left arm has only a leather strap. He has metal shoulder and knee pads, and a large, gold belt buckle with his crest, a Skrill, on it. Dagur wears tan pants and pale green boots with brown bands. He also has a black, studded belt he wears over his left shoulder, which he uses to carry his sword.
In Race to the Edge, Dagur's hair is cut short and sticks up, and he has a short, shaggy beard. His arms are more muscly, as he has been working out during his time in prison. He has a list of names tattooed on his left forearm, most likely his "revenge list."
In the first two episodes of Race to the Edge, Dagur wears the same outfits as in Riders and Defenders of Berk, but without his shoulder pads or left arm bands. His clothing is severely torn.
Later, however, he wears a brown leather and metal tunic with a Skrill chest plate. He has two arm pads as well as similar ones on his boots, which appear to be the same as in previous seasons.
The title of Dagur the Deranged is actually quite fitting, as he is seen as violent and extremely unstable. When he laughs, his smile changes to a frown after a while. At times he performs erratic acts without thought or reason, other than to shed blood and kill. This impulsiveness makes him unpredictable. He might be hyperactive as well as insane. He is especially eager to kill dragons and sees them as nothing more than targets for his sadistic sense of pleasure. It is shown that while Dagur prides himself as a dragon killer, he has little regard for the sport, having brought his entire armada to assist him on his hunt for Toothless. He also has an enormous ego, is very rude, and disrespectful. He also is very vengeful. He also showed a lack of respect for those who were peaceful in his debut.
But behind his insane and sadistic nature, he still has some good in him. Dagur is understandably very fond of his sister, and helped her numerous times. Most iconically, he even dared to go against Viggo's orders to rescue Heather, who was sentenced to death, even though she was siding with the riders.
As displayed in various events, Dagur actually prioritizes family before anything else. He is fiercely protective of Heather, often threatening Ryker not to harm his sister and often reinforcing their bond by saying things like, "Nothing like a family rift, eh, sister?" in "Maces and Talons, Part 1". He also willingly broke out and seemingly sacrificed his life to save Heather, despite her negativity against him, showing just how much she means to him.
- Strength and Fighting Skills: Dagur is an accomplished fighter and has shown to be able to hold his own against Alvin the Treacherous, though he isn't above using unfair means in order to win. He also was able to control a Skrill, by harnessing it and controlling it with ropes. He has better fighting skills than many adult Vikings, such as Savage despite the fact that he is young. He has been working out for the past three years, as his muscles are shown to be a lot bigger and he has grown much stronger as he can knock out dragon hunter with one punch.
- Berserker Rage: As a Berserker, Dagur tends to act savagely, even outside of battle. He enjoys violence of any kind and will even attack his own men. After being imprisoned for three years, these tendencies have intensified. It is possible he actually possesses Berserker abilities, this can be seen when Dagur requests Hiccup to howl with him, like a wolf (úlfheðnar) in "The Night and the Fury", and in their battle near the end he fought like an animal and acted savagely.
- Intelligence: Despite claiming he hates strategy, Dagur is surprisingly clever. He managed to lure Hiccup to Outcast Island, by letting his soldiers tell Trader Johann false information about some kind of weapon that will use against the Riders of Berk in "The Flight Stuff". He also used Trader Johann to bring the Smothering Smokebreath nest to Berk in "Smoke Gets in Your Eyes", so the dragons would steal Berk's weapons, making them vulnerable to an invasion. He also figured out the effect Dragon Root has on wild Dragons, and used this information to get the dragons and their Riders trapped in the academy, so he could trade with Hiccup for his dragon to save his friends. But it was unsuccessful, so he made up for it by capturing Stoick in "Cast Out, Part 1", instead to make another trade.
- Speed and Agility: Dagur has proven in fights against Alvin the Treacherous and several wild Dragons that he is a very fast and agile warrior.
- Leadership Skills: Unlike the Outcasts, Dagur's soldiers appear to follow him out of respect and not fear. However, just like Alvin, his men wouldn't dream of no obeying their leader. The Outcasts join the Berserkers after Dagur supposedly kills Alvin in "A View to a Skrill, Part 2".
- Dragon Slaying: He seemed to enjoy killing dragons. At first, he saw Barf and Belch and was very eager to capture the dragon to slice their heads off but it failed when he saw the dragon attack. As he saw trained dragons that are attacking in the Kill Ring, he was shown to be afraid mostly when he saw the Night Fury and Monstrous Nightmare. But on Dragon Island, he was training for possibly weeks or months to kill dragons and study their abilities. He was able to kill a few dragons like a Monstrous Nightmare, proven by the dragon's skeleton.
- Skrill Controlling: Dagur was able to control the Skrill very well, using the creature like a puppet as Dagur was able to make his Skrill attack everything. However, Hiccup managed to trick Dagur into standing in water as the Skrill attacked, electrocuting the Berserker, who then loses his Skrill in the ensuing chaos.
- Endurance and Stamina: His body is very muscular as he able to endure attacks from other Vikings and continue to fight. He even endures getting shot with an arrow in his shoulder and is later shown to have recovered as he was able to fight once more after the treatment he got from Hiccup. His stamina is very high due to all of the training he has done over the years.
- Dragon Training and Riding: Though very briefly, Dagur showed some signs of being a great dragon rider. His first ride on Toothless was difficult for him at first, although he did improve on the second time. He quickly earned the trust of Shattermaster, who became protective of him, even though they had only been together for one day. He proven to be fast learner according to Fishlegs as he was able to train Shattermaster very fast during the short time they have been together. He was also alble to pick up other skills used by dragon riders during his isolation, like emitting a call to ward off Changewings.
Aside from his absolute insanity, Dagur has an overwhelming sense of pride that prevents him from thinking clearly at times. He tends to be reckless and impulsive and charge headlong into fights where his opponents outsmart him. One such example is Hiccup challenging Dagur to a one-on-one battle between them and their dragons, despite Dagur's overwhelming advantage in numbers. His pride and impulsive nature also make him quite stupid, as he believes that Toothless will just respect him and let him ride without putting up any kind of fight. He also did not question Tuffnut's claim to be a Berserker. However, Dagur slowly began to overcome these weaknesses later on as he turned away from evil, gaining a good semblance of sanity and learning to let go of his pride.
Dagur also tends to lean away from strategy, relying on brute force and harsh attacks to take down a target. He has been seen charging at enemies without regard to his own safety several times. This makes him relatively easy to defeat. Eventually, Dagur overcame this weakness too.
Heather is actually Dagur's long lost little sister. He first mentioned that he had a sister in "The Night and the Fury", who had a shield like Hiccup's. For unknown reasons, Dagur attacked her village and killed her foster family, thus motivating her revenge. Then in "Have Dragon Will Travel, Part 1", he reunited with Heather, who did not know her true connection to Dagur. When he nearly captured her, he told his men he wanted her alive. After Heather learned the truth that Dagur was her brother, he offered her to join him, but she refused. It should be noted that Heather is on his revenge list, though the reason for this is unclear.
Much more confusing, he seemed to be very excited with the fact that his sister is working with him and the dragon hunters despite the fact above. And he even hugged her when he thought Heather was trying get him out of trouble with Viggo Grimborn, though she was actually trying to protect the riders who were captured on the hunters' ship they are also boarding. Dagur also defended her when Ryker suspected of her being a traitor. Most spectacularly, he let his sister go free after he was ordered to sentence her to death by Viggo, after her betrayal was discovered. Though at first he was angry and agreed to imprison her in a cage, he finally had a change of heart and sets her and Windshear free, fully conscious that their allegiance is to the dragon riders, who are his mortal enemies.
Heather became Dagur's reason to change, and began to search around the archipelago to find her. He even asked for the Riders help in a letter once. Dagur was even willing to become a dragon rider to fulfill his mission. When they met again on Dragon's Edge, Dagur was happy to see Heather, but the feeling was not mutual. Dagur tried to convince her he was trying to change, but she still believed he was working for Viggo. When Dagur found out about their mission, he tried to warn them it was a trap, Heather and the other didn't believe him. The they caught him making his way towards the fleet, Heather tried to stop him, but he managed to subdue Windshear long enough to prove he was telling the truth. He ended up sacrificing himself to destroy Viggo's armada.
Before he left, Dagur had written a note for Heather, expecting he would not survive the attack, apologizing to her for what he had done, and that he couldn't risk her life by facing the fleet. He tells about Viggo's dragon auctions, as well as the true fate of their father. Dagur now concludes with him wishing Heather to be safe, proving he had wanted to change and that he really did care about her.
Heather eventually embarks on a journey with Dagur to find their father again, finally realizing that Dagur has changed for the better and that he will likely not survive without his sister.
- "Go, brother. Your dragon needs you."
- ―Hiccup calls Dagur "brother" for the first time in Shell Shocked, Part 2.
Hiccup later meets up with Dagur again on Dragon Island. Dagur is happy to see Hiccup alive after the "attack" and continually expresses shock at how the former fought off a Night Fury. Dagur then decides the two of them will hunt down the dragon together. He even starts calling Hiccup "brother," which the younger Viking found rather awkward. Dagur points out he and Hiccup are a lot alike: both are born leaders, sons of chiefs, and have fathers that had to be eliminated (the last one Hiccup quickly disagrees with). When Dagur learns that the truth about Berk's dragons, he feels betrayed and attacks Hiccup and Toothless. Hiccup beats Dagur, and he and the others head back to Berk, as they need to be ready for when Dagur returns. After being defeated and telling the Berserker armada, Dagur tells them no one is to hurt Hiccup, except him, after he gets his dragon.
After losing the symbol of his people, the Skrill, to Hiccup and Toothless, Dagur's pride was badly hurt, making him even more determined to capture the rider and his dragon. Dagur also tried to make Hiccup choose giving Toothless up for the sake of his loved ones, such as the Dragon Riders and Stoick.
After being imprisoned, Dagur focused on getting revenge on Hiccup more than ever. He also kept calling Hiccup "brother," though more of in a mocking tone.
After his resolve, Dagur tried to prove himself to Hiccup he had changed. He protected Hiccup from a group of Dragon Hunters, as well as come up with an antidote for dragon root when Toothless had been hit by their arrows. When they were captured, Dagur saved Hiccup from being branded and released him, with Toothless' help. Between the two events, Dagur looked hurt when Hiccup shout that he hated the Berserker when he left him behind to get Toothless.
Dagur went to Hiccup again seeking help to become a dragon rider so he could search for his sister. While Hiccup was reluctant, he agreed, much to Dagur's joy. He continued to show gratefulness, and admitted to his mistakes during training. When Dagur learned that Heather was with the Dragon Riders, he was more disappointed in Hiccup for keeping the secret instead of getting mad. When Dagur saw the plans for the Riders attack, he tried to warn Hiccup it was a trap. Dagur later rode out to prove he was right, and to protect his sister, possibly costing him his life. Hiccup was left feeling guilt-ridden for not believing him.
When Dagur returned, Hiccup had doubts about trusting him, but Dagur eventually proved himself to be a worthy ally when needed most.
Dagur is shown to have little respect for his father, due to his father's lack of interest in war. He spends most of his time on Berk disrespecting his father. Dagur claimed to have killed his father so people would think that he was tough enough to be chief. Though he admitted to Heather via letter that it wasn't true, and that he had actually disappeared. This could also mean Dagur also faked his hatred for Oswald to make it believable.
Upon returning to the Edge, Dagur revealed he had been on a quest to find his father, which he planned to continue with Heather at his side.
Despite Snotlout being a great fan of Dagur, Dagur shows little to no interest in him, thinking his name is 'Snot hat' or otherwise incorrectly pronouncing it. Snotlout was also the one who saved the Screaming Death's mother from him. Even after becoming allies with the riders of Berk, Dagur never did get Snotlout's name right, leading to the amusement of many others present (most notably Hookfang, Snotlout's own dragon).
Fishlegs is afraid of Dagur due to the fact that the latter locked him up in a cage and didn't feed him for at least a day and when he did feed Fishlegs, he fed him rotten cod heads. Dagur believed Fishlegs might be useful when tracking down Toothless in The Night and the Fury.
When Fishlegs had to work with Dagur to train Shattermaster, the two bonded quickly and even came up with a new maneuver.
Dagur doesn't like Stoick, having an obvious sense of disdain for Stoick's more merciful and peaceful ways and personality. This dislike turns into hatred as Berk and Berserk become official enemies. Dagur also held Stoick hostage, in exchange for Toothless.
Alvin and Dagur used to be allies, though out of necessity. Both needed each other's forces in order to take over Berk. Both Tribes planned to betray one another afterwards. However, they became official enemies when Dagur stole the Skrill and took over the Outcast Tribe. After Alvin regained control of his Tribe, Dagur was put in jail on Outcast Island.
Following Dagur's victory over Alvin, Savage willing served under Dagur commanding the Uutcasts. After Dagur's defeat by Hiccup, Alvin, and the dragons, he then spent three years in prison with Dagur, his Berserkers and other Outcasts. However, he was freed and went with Dagur and the others to take Trader Johann's treasures hidden in the Ship Graveyard. He continued serving Dagur, even when he questioned his alliance with Ryker Grimborn's Dragon Hunters.
When Dagur discovered that captain Vorg and his crew had found a Skrill, he was overjoyed. Upon hearing the Berkians had said Dragon, he organized an attack on Berk, which soon turned into war. He managed to capture and control the Skrill, but lost it again.
Captain Vorg was the one who told Dagur about the Skrill, though he failed to deliver it to him. Vorg later acts as Dagur's second-in-Command. He respects Dagur greatly. In Race to the Edge, Vorg appears to still be loyal to Dagur.
Before Dagur met Toothless, he didn't think Night Furies even existed. After that encounter, he wanted to hunt him down and slay him. However, upon learning Dragons could be trained, he wanted Toothless to become the new symbol of his tribe. In Race to the Edge, he seems to want revenge on Hiccup more than capturing Toothless, at least for now.
After Dagur switched sides, he tired to help Toothless, who was struck by the Hunters' arrows. He did everything he could for the dragon to feel comfortable and keep him hidden. By this time, Dagur was calling Toothless by name. Dagur helped him recover by gathering ingredients for the antidote. Dagur and Toothless later teamed up to save Hiccup from the Dragon Hunters. When they met up again, Toothless was still at caution, but let Dagur ride him to pass the time waiting for Hiccup.
When Dagur demanded that the treaty had to be signed with Dragon blood, he soon came up with the idea to hunt down Barf and Belch, in order to use their blood. Though he tried to kill them, they managed to escape and defeat him with the aid of the other Riders and Dragons.
When Astrid learned Dagur was coming she said he should be locked up in a cage, and she wasn't happy to learn that Dagur was the new Chief of the Berserker Tribe. Three years after his war with Berk, Dagur captured her and the other dragon riders in exchange for Hiccup giving him the Dragon Eye.
Astrid did not believe Dagur had changed and even thought he was still working for Viggo. Dagur tried to convince her otherwise when she had to keep an eye on him. Dagur was impressed by Astrid's combination of fighting and dragon riding.
Dagur can't tell the twins apart. Several times he has thought Ruffnut was a boy. They also especially don't like him because he was going to kill their dragon.
The three came to terms when Dagur visited Dragon's Edge to learn how to ride a dragon. He seemed to be impressed by the names Tuffnut comes up with.
Viggo and Ryker Grimborn
Sometime during Race to the Edge, Dagur joined up with Ryker and the Dragon Hunters. He seems to be fine around Ryker, even nicknaming him "Rykie", but when he meets Viggo, he seems rather uncomfortable.
When Dagur accidentally shot down Gustav instead of Hiccup or one of the other riders, he was about to throw him to the eels, but Gustav tells him he can help him. Dagur gets the information he wants to get the Dragon Eye from Gustav, but says he's actually going to feel a bit bad when he kills him.
Shattermaster is a green Gronckle that was given by Hiccup for Dagur to learn to be a dragon rider. While at first he didn't want to ride him, Dagur soon learned dragon training was harder than it looked. The two quickly bonded, despite Dagur's need for control. Even though it had only been a day, Shattermaster defended Dagur when Astrid and Stormfly threatened him, much to the girls' surprise. Dagur was able to use Shattermaster to keep Heather and Windshear away from Viggo's fleet. He rode his new dragon into battle to destroy the fleet, though it appeared to cost them their lives. In the fourth season of Race to the Edge, Dagur's relationship with Shattermaster was shown to have increased, to the point where he considers Shattermaster to be his best friend and to have trained him to utilize a few unusual but extremely powerful fighting techniques. When Shattermaster was badly hurt in the final battle between the Dragon Hunters and the Riders of Berk and their allies, Dagur helped get the gronckle to safety and told the dragon that if there was anyone he wanted to go out fighting with, it was Shattermaster.
Dragons: Riders of Berk
- "My father has been... 'retired.' He lost his taste for blood. I, on the other hand, am starving"
- ― [src]
- "Do I look stupid to you?!"
- ― [src]
- "Boring! I want to see the dragon killing things!"
- ― [src]
- "Sounds like my father. 'Sign the treaty, Dagur. Leave that chicken alone, Dagur. Ooh, put down that axe, Dagur'!"
- ― [src]
- "My father was a coward. I intend to return the Berserkers to their former glory. Something he was... incapable of doing."
- ― [src]
- "Ah, Hiccup. There you are!"
- ― [src]
- "Oh, the laughs we had. Bored again!"
- ― [src]
- "Great idea! Let's sign that treaty! Bring out the dragon's blood!"
- ― [src]
- "Run if you want! But Dagur the Deranged will not retreat!"
- ― [src]
- "A Night Fury! They do exist!"
- ― [src]
Dragons: Defenders of Berk
- "Hiccup, old friend! You're alive!"
- ― [src]
- "I'm going to grab my gear. Then we're going to get us that Night Fury... brother."
- ― [src]
- "Hiccup, your definition of 'alone' and mine are very different."
- ― [src]
- "Oh brother, don't you know a trapper's trap can trap the trapper?"
- ― [src]
- "You could've been my brother, Hiccup. Now, you're my enemy!"
- ― [src]
- "No one hurts Hiccup! No one... except me. And not until after I have his Night Fury. And I will have it."
- ― [src]
- "They're regrouping, you idiot! That's it. You're relieved of duty."
- ―(pushes Vorg overboard)[src]
- "Um, didn't I throw you overboard?"
- ― [src]
- "Man, I love it when I'm right!"
- ― [src]
- "Geez Al. Don't get your skivvies in a bunch. Fine, we'll do it your way."
- ― [src]
- "Who is smacking their food? I hate smacking! My father used to smack!"
- ― [src]
- "Execution? Did somebody say 'execution?' Now we're getting somewhere!"
- ― [src]
- "Pucker up, Hiccup, because you're about to kiss my boots."
- ― [src]
- "A spoon?! They're dropping spoons?! Why are they dropping spoons?! What does this mean?! Could this be a spoon of surrender?!"
- ― [src]
- "This is not over, Hiccup! You hear me?! You just wait! You will kiss this boot!"
- ― [src]
- "Hello, Mr. Night Fury. How are we doing today? Happy? Feeling Hiccup-y good? Just a big love fest over there on Berk, isn't it? Well, not for long. That's right, you and I are going to spend some quality time together, ramming it up..."
- ― [src]
- "Hellooo! I'm deranged!"
- ― [src]
- "Hiccup? Brother?!"
- ― [src]
Dragons: Race to the Edge
- "Hiccup! Did ya miss me? 'Cause I sure missed you! Everyday for three years, I've thought about you!"
- ― [src]
- "Look at you! All growed up, and quite the ladies' man, I'd wager?"
- ― [src]
- "See what you did? You distracted me. And now my pretty, cylindrical, mysterious object is gone. Good for you, Hiccup! Good for you! But I got all the gold! You hear me? All the gold! All! The! Gold! [laughing, pushes Savage onto the ground] You know, you can never have nice things around that guy. [steps on Savage]"
- ― [src]
- "Wow, where's the trust? After all we've been through together?"
- ― [src]
- "No Hiccup-y barbs? Quips? Snappy comebacks? But I really love those! We've developed such a nice shorthand, you and I."
- ― [src]
- "Ooh-ho-ho! And the plot thickens!"
- ― [src]
- "You know what I always say; 'When in doubt, take it out'!"
- ― [src]
- "Well, hello, Heather."
- ― [src]
- "And twelve ships trumps two axes!" (sees Windshear and Stormfly) "I really should have seen that one coming."
- ― [src]
- "Heather! I'm the only family you've got left! Join me, sister! Don't fight destiny! I know you feel the Berserker blood flowing through your veins!"
- ― [src]
- "Come back, sis! 'Heather the Unhinged' has a nice a ring to it! No? You'll be back, and I will welcome you with open arms!"
- ― [src]
- "We'll have to wait on that reunion. Pity."
- ― [src]
- "Oh, Hiccup. So soft hearted and soft headed."
- ― [src]
- "Assemble the fleet! We'll scour this area until we find Dragon's Edge."
- ― [src]
- "More dragon riders?! That's cheating!"
- ― [src]
- "Surprise! Did you miss me? Of course you did! Oh, do you know my sister? Wait a minute, sure you do! You guys were little pals, buddy-buddies!"
- ― [src]
- "Ooh, Zippleback boots. I always wanted a pair."
- ― [src]
- "Completely expendable, all three, including 2."
- ― [src]
- "I called dibs already on the hat thing a long time ago! So back it down, big boy!"
- ― [src]
- "Was that Hiccup? Why would he lead a Skrill right to us? It's not my birthday ... is it?"
- ― [src]
- "I keep saying, 'don't underestimate them.' And what do you do?! You underestimate them!"
- ― [src]
- "Let me put it another way. If you touch one hair on my sister's head, I'll run you through and wear your rib cage as my battle armor!"
- ― [src]
- "Well, I let it enter my noggin and pay no attention, right? I mean, that's how you ignore something!"
- ― [src]
- "I am thinking! This is my thinking face!"
- "Newsflash! I no longer care what Viggo has to say!"
- ― [src]
- "Hello, Hiccup!"
- ― [src]
- "Hiccup, I'm not here to hurt you, I'm here to help! Seriously! You need to calm down!"
- ― [src]
- "That stuff can kill you from the inside, Hiccup. Revenge, anger, obsession. Trust me, I know. It can make you do things you never thought you were capable of. Cause you to take chances, make mistakes. And if that doesn't end you, it'll eat at you slowly."
- ― [src]
- "Relax, blondie! I was just trying to talk some sense into your boy Hiccup here!"
- ― [src]
- "Fine. Lock me up, then go do your mission. But know this, Hiccup. If anything happens to Heather, I will hold you personally responsible."
- ― [src]
- "Heather, if you're reading this, I guess that's bad news for me. Sorry, but I couldn't let Hiccup fly you into a trap. Tell our little brother that if he really wants to hurt Viggo, hit his next dragon auction. It moves around, but if he turns over enough rocks, some worm will tell him where it is. One other thing, I didn't kill our father. When he disappeared, I let people believe that, so they would think I was tough enough to be Chief. I did a lot of things I am sorry for, but I couldn't rest in peace knowing you thought I did that. Be Safe. Your brother, Dagur."
- ―(the letter he left for Heather)[src]
- Dagur is the first youngest Viking to become chief, the second being Hiccup.
- He is the first character to enslave a dragon instead of training it, the second being Drago Bludvist, and the others being the Dragon Hunters.
- Dagur has a list of names on his left forearm, possibly his revenge list. The first name is crossed out, followed by "Hiccup." Some of the legible names are "Astrid," "Night Fury," "Fishlegs," and the last is "sister", referring to Heather.
- The first name is crossed out, but is likely his father.
- The fourth name is most likely Alvin, as the first letter matches Astrid's "A", the second letter matches Fishlegs' "L", the fourth letter is "I" as shown on the other names, and the last letter is "N", like the first letter on the word "Night Fury."
- Although Heather is on the list, he was happy that she was 'working with him' and freed her even though Viggo had sentenced her to death. It could be he was trying to find her instead, believing she was still alive when she was separated from her family.
- Dagur is the second character to cut their hair, and the first for it to be permanent.
- When angered, Dagur has a tendency to take out his frustration on his own men, often tossing them overboard, strangling them, or otherwise inflicting physical harm on them.
- It is possible that Dagur is inspired by Norbert the Nutjob from the books, since both characters have many things in common:
- They have alliterations in both their names and their titles.
- Both of them have absent fathers (Dagur's went missing, while Norbert's is deceased.)
- Both of them have mentally unstable personalities.
- Both of them had been struck by lightning, though through different means (Dagur was struck by a Skrill while Norbert was hit directly through his axe).
- Both of them prefer axes as their main weapons.
- Both of them are enemies to Hiccup Horrendous Haddock III and the Hairy Hooligans, though Dagur became an ally before his death.
- Both of them are chieftains to their respective tribes (Dagur to the Berserkers and Norbert to the Hysterics).
- Both of their helmets look almost similar.
- For unknown reasons, in Enemy of My Enemy and Family on the Edge, Dagur's irises are larger and lighter green, like Heather's. This may have been from his change of heart and decision to be kind.
- His hair in Race to the Edge resembles Hiccup's in the books.
- Dagur has been hit in the leg by a Deadly Nadder spine at least once.
|Riders of Berk|
|1. "How to Start a Dragon Academy":||Absent||11. "Heather Report, Part 2":||Absent|
|2. "Viking for Hire":||Absent||12. "Thawfest":||Absent|
|3. "Animal House":||Absent||13. "When Lightning Strikes":||Absent|
|4. "The Terrible Twos":||Absent||14. "What Flies Beneath":||Absent|
|5. "In Dragons We Trust":||Absent||15. "Twinsanity":||Appears|
|6. "Alvin & the Outcasts":||Absent||16. "Defiant One":||Absent|
|7. "How to Pick Your Dragon":||Absent||17. "Breakneck Bog":||Absent|
|8. "Portrait of Hiccup as a Buff Young Man":||Absent||18. "Gem of a Different Color":||Absent|
|9. "Dragon Flower":||Absent||19. "We Are Family, Part 1":||Absent|
|10. "Heather Report, Part 1":||Absent||20. "We Are Family, Part 2":||Absent|
|Defenders of Berk|
|1. "Live and Let Fly":||Absent||11. "A View to a Skrill, Part 2":||Appears|
|2. "The Iron Gronckle":||Absent||12. "The Flight Stuff":||Appears|
|3. "The Night and the Fury":||Appears||13. "Free Scauldy":||Absent|
|4. "Tunnel Vision":||Absent||14. "Frozen":||Absent|
|5. "Race to Fireworm Island":||Absent||15. "A Tale of Two Dragons":||Absent|
|6. "Fright of Passage":||Absent||16. "The Eel Effect":||Absent|
|7. "Worst in Show":||Absent||17. "Smoke Gets in Your Eyes":||Appears|
|8. "Appetite for Destruction":||Absent||18. "Bing! Bam! Boom!":||Absent|
|9. "Zippleback Down":||Absent||19. "Cast Out, Part 1":||Appears|
|10. "A View to a Skrill, Part 1":||Appears||20. "Cast Out, Part 2":||Appears|
|Race to the Edge, Season 1|
|1. "Dragon Eye of the Beholder, Part 1":||Appears||8. "Crushing It":||Absent|
|2. "Dragon Eye of the Beholder, Part 2":||Appears||9. "Quake, Rattle and Roll":||Absent|
|3. "Imperfect Harmony":||Absent||10. "Have Dragon Will Travel, Part 1":||Appears|
|4. "When Darkness Falls":||Absent||11. "Have Dragon Will Travel, Part 2":||Appears|
|5. "Big Man on Berk":||Absent||12. "The Next Big Sting":||Absent|
|6. "Gone Gustav Gone":||Appears||13. "Total Nightmare":||Absent|
|7. "Reign of Fireworms":||Absent|
|Race to the Edge, Season 2|
|1. "Team Astrid":||Appears||8. "Edge of Disaster, Part 1":||Appears|
|2. "Night of the Hunters, Part 1":||Appears||9. "Edge of Disaster, Part 2":||Appears|
|3. "Night of the Hunters, Part 2":||Appears||10. "Shock and Awe":||Absent|
|4. "Bad Moon Rising":||Absent||11. "A Time to Skrill":||Appears|
|5. "Snotlout Gets the Axe":||Absent||12. "Maces and Talons, Part 1":||Appears|
|6. "The Zippleback Experience":||Appears||13. "Maces and Talons, Part 2":||Appears|
|7. "Snow Way Out":||Absent|
|Race to the Edge, Season 3|
|1. "Enemy of My Enemy":||Appears||8. "Stryke Out":||Absent|
|2. "Crash Course":||Absent||9. "Tone Death":||Absent|
|3. "Follow the Leader":||Absent||10. "Between a Rock and a Hard Place":||Absent|
|4. "Turn and Burn":||Absent||11. "Family on the Edge":||Appears|
|5. "Buffalord Soldier":||Absent||12. "Last Auction Heroes":||Absent|
|6. "A Grim Retreat":||Absent||13. "Defenders of the Wing, Part 1":||Absent|
|7. "To Heather or Not to Heather":||Absent|