Denny is Aislinn's friend. He taught her how to play pool and they meet at Shooters on the weekends.

Like Seth, Denny notices Ash's sudden mood changes (due to the appearance of fairies only she can see). And, like Seth, Denny doesn't call attention to them or make a big deal. He does what he can to smooth them over -- for example, asking Grace to play a song for Ash on the jukebox. When it doesn't help, Denny is understanding and lets her call it a night.

It's not clear how old Denny is, but the impression is he's older than Aislinn.