Me, a Reincarnation Possession User!? An Odd Shared Life Beginning from a Reincarnator's Failed Reincarnation?

The perfect protagonist—beautiful in appearance and skilled in both literary and martial arts—had harbored a great secret since childhood. That secret was that "there is another resident living inside him." That suspicious-looking person insists he is a reincarnator who, through the whimsical games of the gods, was equipped with countless reincarnation benefits and attempted to take over the protagonist's body. However, he was defeated in willpower by the protagonist who was only 0 years old. Thus begins the strange cohabitation of these "two people."