Nightshroud

Nightshroud is a villain from Yu-Gi-Oh! GX. He is an evil spirit that has the ability to possess human beings. He was also one of the seven Shadow Riders. He was a minor villain in the first season, but he later returns as the main antagonist in the fouth season.

Shadow Rider
Nightshroud was the first of the Shadow Riders to challenge the "keykeepers" and therefore the first to lose. His shadow charm was the mask that he was wearing to conceal his face. He duels Jaden in the first night, right after Jaden was told about the Shadow Riders. He uses a "Red-Eyes Deck" which revolves around summoning "Red-Eyes Black Dragon". When Nightshroud is defeated, it turns out he is a spirit that took control of Atticus, Alexis long-lost brother.

During the Genex tournament, Atticus duels Zane, and Nightshroud start taking him over again, however, Zane finishes the duel before Nightshroud can take control over Atticus again.