First thing I'm noticing is his power having no limit. You should finish the section, because being able to control people's emotions should theoretically allow someone to take over the planet with ease.
Also, something else - when you're making Ominous' past, it makes me wonder why no one in his early life was a decent human being. Why were his parents abusive? Why didn't students help him? It just makes me wonder. Plus, why is he in trouble, but everything the bullies did before doesn't make them criminals? I like his motive, but these are the main issues I'm finding.
First, His backstory was made this way in order to give him a justified reason to think that everyone in the omniverse and beyond, including himself, was evil or had evil in them that needed to be rectified.
And second, can you give me some suggestions on how to limit his powers to control not just emotions, but morality and intentions? Also what do you mean by motive?
He, judging from his quotes, can act like a child when his ideals are not believed. This leads me to believe that he's really coming with his plan to hide the truth - he's just really guilty about doing what he did the kid.
I have the same opinion on his personality as I do his motive.