Hmm, I'd probably challenge him to a single-adventure D&D game; he gets to DM, I get to use any character I want, level limit 15, and he can't make the adventure with foreknoweldge of my character (but has to make it within three levels of difficulty to level 15). Then I bust out my best friend's most annoying PC; Axel Zade, Leader of Odell. Death's got nothing unless he cheats or makes an absolutely terrible adventure; which, I mean, he's welcome to do... but I'll still feel that is cheating, and even damned to hell for eternity it'll be because not even death could face Axel in a fair fight.