Also according to the two episodes from "Konjaku Monogatari shu," he was the son of TAIRA no Kanetada, Kazusa no suke (Assistant Governor of Kazusa Province), who was the younger brother of TAIRA no Sadamori and the grandson of TAIRA no Shigemori, governor of Mutsu Province, but he was adopted by TAIRA no Sadamori, who adopted many of his nephews, as his fifteenth adopted son, so he was called the Yogo prince.
また『今昔物語集』によると二話とも平貞盛の弟陸奥守平繁盛の孫で上総介平兼忠の子であるが、平貞盛の養子となり、平貞盛は甥達を大勢養子としており、子としては15番目だったことから余五君。