Which Japanese legendary hero killed the demon Shuten-dōji?

The Japanese legendary hero who killed the demon Shuten-dōji was Minamoto no Yorimitsu.

Yorimitsu is better known in legend by his nickname Minamoto no Raikō. In the medieval Shuten-dōji tale, the emperor ordered him to stop the oni leader, whose band terrorized Kyoto and abducted people. Yorimitsu traveled with his Four Heavenly Kings and, in many versions, Fujiwara no Yasumasa.

The warriors disguised themselves as mountain ascetic priests and gained access to Shuten-dōji’s stronghold. They served him specially prepared sake that incapacitated him, then attacked while he slept. Yorimitsu beheaded the demon with the sword Dōjigiri, although the severed head reportedly continued biting at him; several helmets helped protect him.

The story is folklore rather than a verified historical event. Yorimitsu himself was a real Heian-period official who lived from 948 to 1021. Musashi and Minamoto no Yoshitsune are famous Japanese warrior figures, but they are not the hero identified with Shuten-dōji’s defeat.