This sounds like the funnest thing ever.
Edlenn Amarth was a short-lived half-elven cleric (in a short-lived campaign, more’s the pity). The name itself, online fan-dictionaries assure me, means “Exiled Doom” in one of Tolkien’s strains of elvish; he followed a god whose aspects were chaos and war. To cast a spell, he needed to cut himself, and he could sacrifice hit points for extra oomph (a DM ready and willing to hash out house rules for added color is a good thing to have, especially in a lockstep system).
The party got way too cocky and overextended itself into a battle against some youngish sea dragon, who proceeded to lay some serious smackdown. Edlenn took enough damage from nasty hurting dragonbreath to drop him unconscious–but I’d long since arranged with the DM that he would either stand in battle, and when he fell there’d be none of this “stabilize, quaff potion, fall unconscious, stabilize, rinse, repeat” business–if he fell, that was it–meaning that he’d sacrifice all his hit points in a final blaze of glory to his god, with possible good effects for the rest of the party (or not, per DM whim). So he essentially ended up exploding into a fine red mist, the shockwave of which coated the cavern, and had the effect of some highish-level Bless variant on the remainder. A couple other characters died during the course of it, but they managed to pull through.
My replacement character was a rather typical sorcerer–everyone in the group kept expecting me to get disturbingly creepy at some point. His only noteworthy characteristic was shouting out the names of his spells for verbal components. Melf’s Acid Arrow consisted of a panicked and/or angry (depending on context) “Melf MELF MELF!!!”
Good times.