Midori is a cruelly mischievous man shrouded in mystery. He seems to have somewhat sadistic tendencies; deriving happiness from teasing and harassing others for his own amusement, even in life and death situations. He enjoys making others uneasy and playing inappropriate jokes on them.

Midori is rather controlling; preferring to cheat or trick in order to stay in the dominant position. His energetic and playful manner of speaking is often completely oblivious to the dangerous circumstances of their situation, treating dark topics with little weight; often lightheartedly referencing his own death with no hesitation, and making it into a game.

At times he seems to drop the act, mockingly becoming serious to scold participants if they don't follow his orders. However, this emphasizes just how much he patronizes the others. Despite speaking in a cheerful and cool manner, Midori seems to actively disdain Alice Yabusame, his supposed killer.