Thought it might be an interesting match, because Luke has better base durability, but Killian has a pretty potent healing factor, which allows him to heal things like broken bones literally in seconds. So, Luke could put some hurting on him, but he'd have to do something decisive to end it before Killian can recover. And, on the flip side, Luke has multiple solid heat resistance feats (ranging from tanking explosions to smothering gas fires with his bare hands to surviving a super-heated acid bath), but he's never faced the kind of concentrated heat Killian can produce.