Mako makes his first appearance in the Duelist Kingdom season where he duels Yugi near the sea after leading him and his friends near his camp ground. The sea arena allowed all of Mako’s water monsters to gain extra power bonuses as well as the ability to hide beneath the water before they attack. Mako was leading the duel until Yugi found the weakness in his strategy, without the sea his monsters were nothing. Yugi drained the sea with a card combo making Mako’s monsters useless allowing Yugi to destroy them and win the duel.
His second appearance was in the Battle City season where he duels Yugi’s best friend Joey Wheeler. Mako uses the same techniques from before while dueling Joey, using various magic card to create an ocean for his monsters. With the same strategy however comes the same weaknesses as before. Joey drained the ocean allowing his monsters to attack and win the duel.
Mako is later seen throughout the series often in brief appearances such as when watching Yugi and Kaiba dueling with there Egyptian God Cards.
Mako Tsunami appears as an opponent in various Yu-Gi-Oh games. He mainly uses a water deck based around his favorite card “Legendary Fisherman”.