Koakuma (EntityTopic, 8)
From Compile Worlds
Koakuma is either a mischievous fairy-like prankster or very loyal for a devil. But since it's canon that matters, Koakuma is one of those wimpy Little Devils that somehow got found working with Patchouli. But knowing her, she must play lotsa pranks and games on her free time, given that they don't involve her master's work.
For some reason, she has devil wings as ears. But some people prefer her with devil wings on the back too. Even Inaba of the Moon & Inaba of the Earth chapter 23 shows her with both! But other than that, we don't really know who she really is. Whether ZUN will give her another appearance like what he did with Daiyousei, a fellow midboss from the same game she appears in, time will tell.