So, one, the best running joke on televisi (besides Neil Patrick Harris being perpetually cast as an intense heterosexual) is how the Misfits crew constantly kills its probation workers. That being said-- the mysterious stranger seems like he's obviously their new supervisor-- he's the only new, white character that's been introduced so far, and if anda notice, he goes out of his way to try and kill Nathan (i.e. he knows Nathan is immortal) even though Kelly's the one that attacks him, and his character appears intensely disinterested (perfect for a character whose obsessed with the group).