Sauron's lack of Death...

[Sarumian]

Originally Posted by Hookbill

So often in an adventure of this kind (evil tyrant seeks to destroy / take over world), the antagonist is killed by the hero. This is another way in which The Lord of the Rings differs itself from many others.

This observation leads us to the exciting and complicated question of what is death in the Tolkien's universe. Not going into details we can state that death there means separation of a soul from a body; in case of Men it is irreversible, though Elves theoretically could return to their bodily shape. Anyway even for Men death never meant elimination of spirit, but rather the departure from Arda and return to Eru (the Creator). Moreover, the separation can be either voluntary (elves) or compulsory (men).

Dealing with ainur makes it quite a tricky matter. Valla Melkor, the first Dark Lord, surrendered to Vallar's Great Host, wasn't properly killed, as it seemed to me, but rather made motionless and was cast into Void in his physical body. Sauron's destiny could've been something similar, had he surrendered, but that was never the case; thus the fight continued to the point where Sauron was unable to perform any physical act or to force any living creature to do something by his will. Sauron's capacity of living and acting was tied to The Ring since he had forged it. Sauron's counterparts had two options for winning: to use The Ring against Sauron (which would have left him alive, though enslaved) or to destroy The Ring (that led to the destruction of Sauron's body and diminishing of his spirit).

To sum up, Sauron died several times during the First and Second Age, but was able to restore his physical presence till his defeat in the War Of The Ring. On the other hand, his spirit had never died as any other spirit in Tolkien's universe. Neither Saruman's spirit was dead after he was murdered by Grimma, nor Gandalf's soul perished after the battle with Balrog. But it looks that fallen spirits were sentenced to stray in the world, suffering their own misery with no chance to influence anything.

What I am not sure about is the exact way of dying for

embodied Ainur;
elves;
men;
dwarves;
ents;
orcs

What happened to them?