A Wishing Shadow

Ever since a golden meteor crashed the moon and turn it into oblivion and become Earth's new moon, the world changed where you can give life to something, and it would serve you for a lifespan. Such something was called Tsukumogami. That was such a world Cell, real name, Saibo Hei living. Humans can give life to something when they hit nineteen and are obliged to enroll in a special school. Based on how you performed, you could get a top position in society or the opposite. There's an easy way to get it, by entering a tournament where you fight with your Tsukumogami. To win, one must fight the toughest people out there. Don't want to deal with it, Cell made a wish to his shadow. In five months, he got what he wished for at the cost of his precious memories, and he regretted it. Waking up in the hospital with no precious memories, he soon met his long-lost twin sister. He was taking a smoke outside of the hospital when a fateful encounter occurred. It awakens his forgotten memories of when he was a child to his teenage years. Human experiment when he was a child, made a deal with a certain radical group when he was eleven, made enemies of both yakuza and mafia groups, and probably much more. He had no idea how his memories disappeared, but he had a feeling it had to do something when he make a deal with that radical group. With his peaceful life at stake, he walked forward to face his problems, only to find out he'll never have a peaceful life again.