Rare Hunter 1

Seeker is one of Marik's Rare Hunters in Season 2 of Yu-Gi-Oh, Battle City.

The Anime
Seeker is the least formidable of Marik's Rare Hunters, but has three sets of Exodia cards in his deck. However, it is later revealed these cards are fake, and the cards are marked. Seeker jumped Joey Wheeler on his way to see his sister Serenity, and dueled him. He won using Exodia, and took his Red Eyes Black Dragon.

Yugi dueled him at the start of Kaiba's tournament, Battle City, but he forbad Joey to tell Yugi that he had Exodia in his deck, threatening to tear his Red Eyes to pieces if he did. However, Yugi figured it out anyway, and became the first person to defeat Exodia in any way, and won the duel. As punishment for his failure, Marik took over his body and banished his soul to the Shadow Realm.

He later appeared as a lost soul in Season 4, Waking the Dragons, as Yami was trying to get to Yugi in a circle of lost souls, however it is likely that he was just an illusion, as many of the others were neither dead nor in the Shadow Realm or taken by the Orichalcos.