TH 1
Tyranno Kenzan (Tyranno Hassleberry in the english dub) is one of the main characters in Yu-Gi-Oh! GX. Although he appeared in the anime, he was not in the manga.

In his first appearance, he was a bully in Ra yellow who often stole the duel disks of duelists he beat in a duel.  Judaii Yuki(Jaden yuki in the English dub) duels him and defeats him.  This earns Judaii Kenzan's respect and becomes an ally.

This put him at odds with Sho Marufuji (Syrus Truesdale in the English dub), because both wanted to be Judaii's best friend. Kenzan plays with a dinosaur deck and has a fascination with dinosaurs.  In fact when he was younger, he was in an accident and had his shin bone replaced with that of a dinosaur bone.  This awakened great power in Kenzan, making him immune to Takuma Saiou's (Sartorius in the English dub) mind control and temporarily transformed him into a dinosaur duel monster.