Ibaraki, Osaka
As for the birthplace, there are theories that it may be Settsu Province (Mio, Ibaraki, Osaka, and Tomatsu, Amagasaki, Hyōgo) or Echigo Province (Niigata, formerly Tochio, now a settlement in Karuizawa, Nanago). Ibaraki-dōji had teeth since birth, and was feared for being a giant. After they became an oni, they met Shuten-dōji and became his subordinate, and together they aimed for the capital. Their gender is ambiguous, in some stories Ibaraki is a kijo (female oni), and in others a male. The female version is theorized to be Shuten-dōji’s lover, son, or his son's lover.