Ousu, son of the twelfth emperor Keikō, was a youth of terrible ferocity. When his father told him to “instruct” his brother, who had stopped coming to meals, the prince ambushed him, tore off his limbs, wrapped him in matting and threw him away.
Frightened of his own son, the emperor sent the boy west against the Kumaso with only a handful of attendants. It was banishment in all but name.
Stopping first at Ise, the prince received women’s robes from his aunt Yamatohime. Arriving among the Kumaso, he found a banquet being prepared for a newly built hall. Letting down his hair and taking the form of a girl, he slipped in among the guests.
The Kumaso brothers were charmed by the beautiful “girl” and seated her between them. When the feast was at its height and their guard was down, the prince drew a sword from his robe and ran the elder through the chest, then pierced the fleeing younger brother from behind.
Dying, the younger asked his name. When the prince answered, he said: “West of here there were none stronger than we two. But in Yamato there is a man braver still. From now, take the name Yamato Takeru.” With those words he was cut apart like a ripe melon.
So Ousu became Yamato Takeru. On the way home he befriended Izumo Takeru, secretly exchanged his sword for a wooden replica, proposed a trading of blades, and killed him.