These artifacts also generally raise the stakes of the game to death and damnation. While the monsters are usually just holograms, various magical artifacts can render them real, complete with the ability to injure the players.
Kaiba then set out to reproduce this effect through holograms as part of his plan to get revenge on Yugi, and the resulting technology was used for the rest of the franchise. In the manga, the first game of Duel Monsters that Yugi played against Kaiba was played as a Shadow Game in which the monsters on the cards were brought to life in front of the players.The anime had a filler arc where Yugi is forced to play Duel Monsters inside a virtual world. Yugi and his friends are sucked into a board game in the 'Monster World' arc of the Yu-Gi-Oh! manga.Kamui: Planet Cray? Isn't that the planet they made up to explain the Vanguard cards?