During the Duelist Kingdom tournament, Mako used a Deck comprising of sea creatures. He took advantage of the field bonus element of the tournament by Dueling near water to ensure his monsters were hidden under the water field and gained field power bonuses. He had no Magic or Trap Cards shown in his Duels.
in Yu-Gi-Oh! Duel Monsters, Ryota Kajiki appears as an opponent in the sea area of the Duelist Kingdom island. Ryuzaki uses an Water-themed Deck. His strongest card is Octoberser, and his only card carried over from the manga is Jellyfish.
Mako appears in Dark Duel Stories as one of the first tier opponents. True to his appearance in the manga, his deck is centered around water-type monsters, with his signature card shown to be Fortress Whale. Another key card he used in Battle City is Umi.