huh?
sauron starts off as a humanoid, hedges all his bets into the One Ring, loses it and his body and the comes back as big burning eye o fire. lets a coupla hobbits toss the ring into a pit o lava and falls down and doesn't get up.
there's the Mouth o Sauron, who isn't sauron per se.. but.. the mouth of...
and there's the witch king, the guy on the big fell beast with the sword o flames, he's a human king who was corrupted by one of the rings o power given to the human kings of that time, he leads the other naz'guul.
In the books Sauron had a new body already by the time of ROTK.