He came from a family of lower-ranking nobles (some literary scholars such as Susumu NAKANISHI stated that he was a naturalized citizen from the kingdom of Baekje), and his kabane (hereditary title) was Omi.
下級貴族の出身（中西進ら文学系研究者の一部からは百済系帰化人説も出されている）で、姓は臣（おみ）。