: I think the SB explanation is simple. He's alive. He's
: preserved by some bizarre ritual whereby he mutilates
: himself and eventually cuts out his heart, which is
: STILL ALIVE and beating back in his temple. (This was
: the whole point made to Miguel back at that old
: MacWorld; he cut out his heart so that the only way
: anyone could ever truely kill him would be to find his
: heart and kill that too). Unhealing hurts him because
: it's healing the wounds that are sustaining his life,
: so he turns to crows and runs away before he can be
: healed fully healthy and die.
This is the same basis on which healing kills unliving and undead creatures. Their bodies have been altered so that they function in a different fashion from normal living beings. Healing causes their bodies to regenerate toward normality, but in the transition between a living form and an un-form they aren't capable of survival as either and they die.
As for his unkillability, I don't think that has much to do with whether he's living or unliving. That just ensures that all his deaths are like Shiver's...his spirit's anchored and he can come back if a body is again provided. It certainly didn't seem to allow for any impressive resurrections in-game.
--SiliconDream