4. More Powerful than Zalgo
Are you kiddin', mate? Why are you makin' an OC who's much stronger than Zalgo himself? Are you a god or somethin'?
You could even defeat Slenderman with your bare hands. I think that's too much. Stop. Please. I hate very powerful OC's. Super powerful OC's just kill other characters like they were just flies and useless in the story. I mean, where's the thrill? The challenge? Even the great Freddy Krueger himself has a weakness—he can't kill you when you're awake.
Here's the scene:
Girl meets Jeff or any random monsters. She puts up a fight and ends up winning. Others will compliment her 'cause she's awesome and strong like that. Then she'd start killing her enemies, too. I'd kill this blonde 'cause she's like this and like that. Then Jeff and her will fall in love. Then it gets boring and blah blah blah.
Pfft! Super powerful characters are boring! Keep that in mind, mate.
If you're going to make your OC the strongest creature ever, at least give a reason. The reason must be always there. It's the foundation of your story.
Now, don't act like a god, 'cause you're not. Don't be cliché.