Ōtakemaru is a kijin-an oni so powerful and violent that he is considered both a demon (ki) and a god (jin). He lived in the Suzuka Mountains, on the border of Ise and Ōmi provinces, during the reign of Emperor Kanmu (781–806).

Although his legend is not so well known today, he was once considered one of the most fearsome yōkai in Japanese history. Along with Shuten dōji and Tamamo no Mae, it is part of the Nihon san dai yōkai, the Three Great Yōkai of Japan.

the emperor raised an army of 30,000 horsemen to defeat this evil being. However, Ōtakemaru was so powerful that through his dark magic he unleashed a great storm. Lightning and fire annihilated the great army.

He was defeated by the shogun general Tamuramaro who with the help of the goddess Suzuka Gozen managed to cut off his head.

His spirit traveled to India for a time, then he returned to Japan. He reconstructed his demonic body.