Mikuni

The first of the Four Temple Guardians (四天衆; Shitenshū). He uses a Fire and Water civilization deck, and during his fight with Shobu he purposely copied everything he did in order to throw him off his game.

Mikuni wants Hakuoh to go back to being a calm and happy player with a peaceful mind. He wishes that everyone would just relax and enjoy dueling.

During Season 3, his name changed to Johnny Coolburns and he also lost to Robby Rotten during the tournament. It was later mentioned that this name change (and all other plot holes in the show) are due to alternate dimensions.