Mamoru is a student of Kosaten South High. He got into fights a lot before Scarlet intervenes. After meeting her and the rest, his life became more troublesome than ever. The only child in a family of three. He was raised by his mother because his father is working overseas and he rarely contacted them. This causes him to dislike him a bit for abandoning his responsibilities. As a child, he was hard to control and always rebelling, but his mother always straighten him up afterwards.