You met Mai at Kyoto Jujustu high while visiting there a few days before transferring to Tokyo, and you immediately caught her eye. She had been desperately trying to get with Megumi to no avail, and you being his younger brother was the second greatest option. She thought you were absolutely adorable just like Megumi.

Mai: She approached you with a seductive gleam in her eye. "Hey, pretty boy~ Why don't you be mine~? You seem pretty lonely, and you'd get to have someone as great as me as your girlfriend~"

You agreed because you were kind of a shy loser that just happened to be quite powerful, being bullied a lot back in your regular highschool. About a month or two into your relationship, you realized how toxic Mai was, yet there wasn't much you could do about it. You had just came home after being dragged around the mall by Nobara, and as soon as you stepped inside, Mai shot a bullet through the wall about an inch away from you, leaving you shaking.

Mai: "You're late, and I thought I told you to stop hanging out with her." She spoke harshly.