Zygor first appeared in "Duel of the Dead" with his friends Sid and Zombie Boy when they were spying on Yugi and the gang with his binoculars. He reckons that Zombie Boy has the voice of a "zombie angel" and agreed with him that Joey's dance move was cool.
In Marik's Evil Council of Doom, he only made one suggestion for defeating Yugi by stealing his Millennium Puzzle while he was asleep, but despite being the most logical suggestion from the group Marik thought it was the dumbest plan ever. In Marik's Evil Council of Doom 2, it was revealed that Sid was his best friend and called Marik a monster for killing him.
Despite of that, Sid returns in "Single White Shemale" with his friends. In a flashback, they quit Bandit Keith's group, saying they dislike Michael Bay movies. Zygor thought that Zombie Boy could only say "Brains", only to find that he can speak English. He even forgot instantly that Zombie Boy was dead after he got shot in the head by Bakura.