Izayoi is a young boy with strong psychic powers (Esper). Maybe for that reason he is always bored since there is no one who can challenge him, until he is summoned to another world, the world of Little Garden, by Black Rabbit. There, he aids the 'no names,' a community that was destroyed by a demon lord.
Some years before, Izayoi started a certain game: "Try to find me". He was also going to pay some money if someone discovered him. At the same time, if nobody came he was going to do some rampage because the world was too boring for him.
Canaria, Izayoi's adoptive mother, discovered him three minutes before the time limit. She made him admit defeat, after all Izayoi had made this game to challenge someone who could be on the same level as him. Then Canaria proposed that she was going to host a game with him. If she won, she would gain a son, if Izayoi won, she would play with him for the rest of her life and even provide a wonderful place for him. With this they both went around the world for 2 years, until Canaria made an orphan institution to help children like Izayoi.
It is later revealed that his real last name is "Saigou."
His Gift comes from a ''Perpetual Motion Machine'' inside his body, which is in the form of nanomachines.