Dox, known in the manga and Japanese version as Kyuu (宮), is the younger of the two Paradox Brothers. He and his brother duel as a tag team, and appear to duel the protagonists in both Yu-Gi-Oh! and Yu-Gi-Oh! GX. Dox has the kanji for half of the word "Labyrinth" on his head, with his brother's head having the other half.

He and his brother were hired by Maximillion Pegasus to work as Eliminators in his Duelist Kingdom tournament. The two duel as a team, with their "Labyrinth Wall" card enabling them to change the playing field to resemble a complicated underground labyrinth, making game-play more akin to a board game than a card game. The two guard an underground area of the island.