I am the Kat that Walks By Itself

Is he unkillable? I admit he did cross my mind, but I didn't feel like going back and checking up on whether it said he was unkillable or whether he was just a non-aging sort of immortal. I guess it does seem more likely that he's unkillable, otherwise he'd probably have suicided when those long, wet Sunday afternoons got too much for him.