Thuggory is a member of the Meathead Tribe, son of the chief, Mogadon. His Dragon is a Monstrous Nightmare named "Killer". Thuggory appears in the first book and is later mentioned on fifth one, chatting with his father and Madguts the Murderous before The Thing.
Thuggory is among the Meathead Tribe boys who came to Berk to take part in the rite of passage. Thuggory, along with all the other trainees, were banished when they failed to control their dragons. Thuggory is the only one to defend Hiccup when Snotlout blames him for their banishment. Thuggory is also the first to go along with Hiccup's plan to deal with the Green Death, admonishing Snotlout for not even bothering to listen. Thuggory later attends Toothless' "funeral", when it appears he has died fighting the Green Death, only to witnesses Toothless' revival.
He appeared again in How to Steal a Dragon's Sword where he joined the other Warriors-in-Training against the first strike of the Red Rage. Aftere it was over, he was telling the others that Hiccup was surprising cool.
Thuggory also appeared near the end of How to Seize a Dragon's Jewel as the first to accept Valhalarama's new law that the Slavemark be changed to the Dragonmark, as a sign to those who chose Hiccup as the King of the Wilderwest.