Panik is a player eliminator hired by the Duelist Kingdom. He was defeated by Yami Yugi and his soul was sent to the Shadow Realm.

Yu-Gi-Oh! Duel Monsters centers around the journey of the spirit of an ancient Egyptian pharaoh who is trying to re-discover who he was many years ago, since he has lost his memories. With the help of a boy, Yugi Mutou, the one who awakened the spirit, and his friends, he battles many villains and adversaries. Many of the villains have been linked to the Nameless Pharaoh's past, due to the Millennium Puzzle he holds and many try to take the puzzle and his power away from him. 
The series focuses on the card game aspect of it and the main theme represented throughout the series is friendship.

David Moo is a voice actor who works on the properties of 4Kids Entertainment and Central Park Media. He eventually quit voice acting to work as a mixologist and bar owner.

Bruno Mullenaerts is a Belgian voice actor and ADR director. He was notably the voice of Jacky and Harisson in the animated series Pokémon, but also the 1st voice of Shanks Le Roux in the second dub of One Piece, and most well known as the voice of Shinichi Kudo, the famous detective from the manga and the detective series Detective Conan. 

10th grader Yugi spent most of his time alone playing games--until he solved the Millennium Puzzle, a mysterious Egyptian artifact! Possessed by the puzzle, Yugi becomes Yu-Gi-Oh, the King of Games, and challenges evil-doers to the Shadow Games--weird games with high stakes and high risks! These graphic novels contain new stories not seen in the anime, including the origin of Yugi and his friends!
 
(Source: Viz Media)
 
Notes: 
- The Viz Media release split the series into three parts with separate chapter/volume counts. "Yu-Gi-Oh!" includes volumes 1-7, "Yu-Gi-Oh!: Duelist" includes volumes 8-31, and "Yu-Gi-Oh!: Millennium World" includes volumes 32-38. 
- The final chapter of Viz Media's "Yu-Gi-Oh!" was moved from its final volume to the first volume of "Yu-Gi-Oh!: Duelist."