Well, he's already got a fledgling friendship going with Carrie, so that's an in right there with the bat-crew, maybe. Mostly when I say being sneaky it's a general propensity to lurk around semi-invisible via his magic. He's not a bad guy at all, just surly and reclusive. It's possible they could end up working together (this might end up playing out more in missions), or he could uncover her secret identity somehow, if you're up for something more antagonistic.

Awkward roommate things are a good start though.