As the first part of the Dragon Initiation Program, Snotlout captures a Monstrous Nightmare from the Dragon Nursery, despite a longstanding Viking tradition stating that only the son of the chief can possess a Monstrous Nightmare.
"Adieu, Snotlout. I could not have done this without you"
Showing that Hiccup forgives Snotlout for the years of hatred between them.
Unlike his cousin Hiccup, Snotlout is strong, hearty, and excels at being a Viking. He is rather muscled for his age. He has a very large nose with wide nostrils.
"Somebody like Snotlout, for instance, was tall, muscley, covered in skeleton tattoos, and already had the beginnings of a small moustache. This consisted of a few straggly yellow hairs clinging to his upper lip and was deeply unpleasant to look at, but still impressively manly for a boy not yet thirteen."
―How to Train Your Dragon
Snotlout is a bully, fully adhering to the survival of the fittest attitude of the Vikings - only the strong can belong. He is extremely competitive, but also feels pressure to be noticed, as he is only the second in line for the chiefdom on Berk.
Snotlout hoped to be the chief of the Hairy Hooligans one day despite the fact that Hiccup was the true heir; however, if something were to happen to Hiccup, Snotlout would've been next in line for the position. The two were well aware of this fact which spawned a hatred between them. However after his death Hiccup forgave Snotlout for the years of hatred between them. Hiccup even tells the tribes of the archipelago on the Island of Tomorrow of Snotlout's sacrifice.
Snotlout's father Baggybum was always very proud of his son for always being the best of the young Vikings. But after Snotlout betrayed his tribe and joined Alvin and his mother, Baggybum became very disappointed in his son, as seen in the Amber Slavelands. Though after Snotlout's sacrifice, Baggybum once again became proud of his son for his redemption.
Though Snotlout and his film counterpart have many similarities, they also have many differences which include:
The fact that in the franchise, Snotlout doesn't really hate Hiccup, he just looks down on him and mocks him, and at the end of the first film the two even become friends. While in the books Snoutlout legitimately hates Hiccup and wants him dead. Though this is resolved in the final few chapters of How to Betray a Dragon's Hero.