Have some plot going on that needs a clear antagonist you don't have? Or maybe the bad guy just isn't as epic as he could be. Maybe your problem is even that you need an excuse for someone in a moral gray area to do something terrible.
I have a solution that can benefit us both! Basically, I am, full-time, volunteering Ganondorf to be a dick behind the scenes for any subplot involving any characters. As long as there's some way we can work out for him to profit off of it, he'll stick is hands in anything.
To be as IC as possible, half the time he should jump completely out of nowhere towards the climax revealing himself as the mastermind of the whole damn thing, so comments are screened. If he needs to be on-screen in relation to the scheme before that, that's fine, but if there's some chance of it