Mr. Stein

This teacher is only seen in season 3 but the flashbacks indicate he was there in the 1st year as Chumley is in one of the flashbacks. He dies after losing a duel to Jaden Yuki as he Picks up his Scar Knight card and falls into an abyss. In episode 139 he is seen when Jim Crocodile Cook uses the Eye of the Orchlium to see into Jadens mind. His deck is based on turning his opponents monster against them