Enki

is a Boss Yo-kai.

Origin
Enki, like all other Boss Yo-kai of the Iron Oni Army, is based on the legend of Fujiwara no Chikata, a politician of the Asuka period who led a rebellion against Emperor Tenji with the help of powerful magic. He had four oni servants at his disposal: Kinki (金鬼, "iron oni") had a body of steel no arrow or blade could pierce; Suiki (水鬼, "water oni") could manipulate water streams and freeze anything to the core; Fuuki (風鬼, "wind oni") could generate gales strong enough to crumble castle walls; and Ongyoki (隠形鬼, "hidden oni") could erase its presence and strike from the shadows. In some versions of the story any one of them is replaced by Enki (炎鬼, "flame oni") who could rain scorching fireballs on entire armies.

Fujiwara no Chikata was nigh-invicible, but the hero Kinomoto'o managed to seal his oni servants one by one, and he was finally captured and executed. His head was thrown in a river, but it is said it went against the current and floated upstream.