Growing up in Ryūgakure was tough, everyone teased and picked on him for being a soul hunter. Though picking on him for being a soul hunter was a portion, it was actually because he was very bad at it. Though, his life changed after meeting Sigma Uchiha. When he and Sigma battled, the Outer Path forced itself out. Making a deal with Rei, that he'd make him the best soul hunter there was seeing the potential within him. Taking the deal, Rei has become a elite soul hunter, and seeing as to how he met Sigma, he has called Sigma "Lord Sigma".