[quote=@BKburke]
*sigh* If I had known it would be so easyou for the party to find out he was a demon, I never would added that item to my list in the first place. That makes one useless enchanted item that was a waste of space. Well make it two, the ring doesn't have a point anymore either since the statue gives incredible knowledge of magic that could lead to extreme power, that makes two useless items that were a waste. 
[/quote]

Being able to completely hide that you're a demon would take some very strong magic, especially if it was taken from the context of my canon. Demons are fundamentally different than humans; the way the magic works means that if you were to 100% remove all traces of demon from someone, they wouldn't be a demon anymore period, which would make your ring able to convert him from one type of being to another. That sort of magic would make the ring suspect to those who can tell that certain items are more powerful than others. Not wiping out every single trace, magic and physical, that he is a demon would be to use illusion to some extent, which is only so effective. As it stands, the ring is able to make an effect that is more convincing than the usual illusion, and may as such come in useful for blending into most contexts, though you're probably not going to fool an expert.

If this logic is invalid do explain how the ring's magic operates, because if the above doesn't apply I don't understand how your ring works at all.