Jingo

Jingo is a fox spirit originally from Korea who fled to Japan hundreds of years ago. He is a shapeshifter who feasts on human flesh. His favourite snack are human hearts. He has lived for 500+ years already so he knows a lot, his memory is very good. He basically never forgets anything ever, which makes it hard for him to get rid of traumatising pictures of his past.

Jingo only has four tails, which he disguises as blue flames floating around him. The two flames that float over his head are fox-fire (his magic), he keeps them there because he thinks it looks cool.

Jingo's magic is 'Dark'. It's the magic of the void. Using this kind of magic he can cause blights, drain life, summon creatures of darkness, slip into shadows to vanish, and drain the light from areas.

Basic info: Korean fox spirits are called Kumiho. The kumiho shares many similarities to the Chinese huli jing and the Japanese kitsune. In contrast to the other two a kumiho is mostly treated as a malignant figure, a purely evil creature. They are said to be bloodthirsty. The most distinctive feature that separates the kumiho from its two counterparts is the existence of a 'yeowoo guseul' (여우구슬, literally meaning fox marble/bead) which is said to consist of knowledge. According to Korean mythology, the yeowoo guseul provides power to the kumiho and knowledge (and intelligence) to people if they can steal and swallow one. The kumiho can absorb humans' energy with it.