Rex Raptor is a minor antagonist in the Duelist Kingdom Arc which is the first story of the anime Yu-Gi-Oh. He was alright for a minor baddie.

Before the series starts, in the story he was a very respected champion in Duel Monsters. One of the few contestants for the Duelist Kingdom to actually get a real room on the boat. Mai Valentine challenges him to a duel for the room and offers him a kiss in the English dub. But I hear the Japanese version, she offered ANYTHING he wanted, LOL. Either way, (due to her cheating) she wins the room and Rex is unloved and evicted.

His most memorable event was against Joey Wheeler who was the obvious underdog in the fight.

While the Red Eyes Black Dragon isn’t as cool as the Blue Eyes White Dragon, Joey defeating it and then it becoming his staple card was pretty cool.

He shows up briefly for Battle City and I think he actually ends up helping Joey, if I remember it right.