Skeleton King's ultimate ability, Reincarnation, is triggered upon death if you have the right amount of mana. Does this count as an actual death, in that it yields experience and gold to the slayer(s), or is just the "definitive" death that counts? Also regarding the Divine Rapier, is it dropped only upon the actual death?
It won't count as a death/kill and you will retain all "droppable" items same as you would by holding Aegis of the Immortal. Note that reincarnation won't trigger unless you have 140 mana, and that it triggers before Aegis of the Immortal if both are active.
This death won't earn any experience or gold to the hero that slain you.