He is a Konohagakure shinobi. He's also a team-mate of Boruto Uzumaki and Sarada Uchiha. Born in an unspecified village, Mitsuki, under unknown circumstances, became a shinobi of Konohagakure, where he currently resides. In the end of Boruto: Naruto the Movie, it is revealed that he is the son of Orochimaru. In Naruto Gaiden: Michita Tsuki ga Terasu Michi, it is revealed that Mitsuki is a synthetic human created by Orochimaru. (Source: Narutopedia)