Don't know if yours is really considered a demon
Lines and right side not mine.
Mine is a water demon, demon with water powers (and coloration).
They have purple blue eyes, an axe handle shaped end to the tail, and a fox mask, as well as bigger ears.
The eyes look purple, but they really are purple blue.
The cheek marks of the mask may be hard to see, its two stripes on each cheek of the mask.
They can't lift their tail upwards, but they can swing it back and forth in an arc (like a swinging axe or whatever),so the lighter blue there is at the bottom of the tail, not the top.
That's it, aside from I think I may name them Ray or Rey.