Ibaraki-dōji
Ibaraki-dōji (茨木童子 or 茨城童子 "Ibaraki child") is an oni (demon or ogre) featured in tales of the Heian period.
The gang ran amok in the capital, kidnapping families’ girls among other things, but they were destroyed by Minamoto no Yorimitsu and his four vassals, the Four Guardian Kings.
However, when, one time, he left the Yahiko-jinja to return to his home, his mother found a "love letter smeared with blood" hidden in his luggage.
At that time, Shuten-dōji heard about a girl who died from pessimism from not receiving a reply to her love letter, and upon opening a tsuzura within the letter, a strange smoke started rising, that he lost his consciousness, and before he knew it, became an oni, and thus fled the shrine and went about to reach the extremes of evil.
Perhaps as a result of suddenly recovering his memories of his childhood, he promised not to tread that land again, went to Togakushi, Shinano and other places, and aimed for the capital.
Also, in the Settsuyou Kendan, Ibaraki-dōji was a native of Matsumura, Kawanabe (Tomatsu, or a part of the city of Amagasaki), but was born with fangs and long hair and a glint in his eye, and power that was greater than that of grown-ups, that his family was fearful of him, and left him around Ibaraki town, Shimashimo, and then picked up by Shuten-dōji.
According to the legend in Ibaraki city, Ibaraki-dōji was born in the town of Mizuo (now Ibaraki city), but after a difficult delivery after 18 months, he had already grown teeth, and was immediately able to walk after being born, and laughed with sharp eyes upon looking at his mother, causing his mother to die of shock.
The damage caused by Shuten-dōji's gang was so large that Minamoto no Yorimitsu went to exterminate oni, and his subordinates, the Four Guardian Kings, and his friend, went to Mt.
Dressed as mountain priests, his party received help from various people, and pretending to request lodging, successfully got to Shuten-dōji's stronghold.
That evening, they roused up a drinking banquet, and deep in the night, Shuten-dōji, so drunk that he was unable to move and his oni were all exterminated.
Ibaraki-dōji, holding the arm, flew up in the air, broke the gable, and disappeared in the distance in the sky.
The story of Watanabe no Tsuna cutting off Ibaraki-dōji's arm has a variation including Rashōmon gate of Kyoto.
Ibaraki-dōji appears in Type-Moon's Fate franchise as a Berserker (original form) or Lancer (Summer event) class Servant in their mobile game Fate/Grand Order.
