What is an demon ogre?

Oni (鬼おに) is a kind of yōkai, ogre, or troll in Japanese folklore. They are typically portrayed as hulking figures with one or more horns growing out of their heads. Stereotypically, they are conceived of as red, blue or green-colored, wearing loincloths of tiger pelt, and carrying iron kanabō clubs.
Depictions of oni vary widely but usually portray them as hideous, gigantic ogre-like creatures with a single horn or multiple horns emerging from their heads, with sharp claws and wild hair.

They are often depicted wearing tiger-skin loincloths and carrying iron clubs called kanabō (金棒).[2] This image leads to the expression "oni with an iron club" (鬼に金棒, oni-ni-kanabō), that is, to be invincible or undefeatable.

Their skin may be any number of colors, but red, blue, and green are particularly common.They may sometimes also be depicted as black-skinned, or yellow-skinned.

They may occasionally be depicted with a third eye on their forehead, or extra fingers and toes.