Kairoz

Kairoz was killed by (spoilers!) Garrosh in Robert Brooks' new tale: Hellscream.

A link to it can be found here: http://us.battle.net/wow/en/game/lore/savage-world/hellscream/page-1

I'm sure he didn't want to waltz around looking like an elf on a planet where elves don't exist. Would kind of defeat the purpose of being disguised. I agree with Gimmicka, the bigger question is why is he dead. I suspect he just outlived his usefulness.

Okay, to sum it up.

Kairozdormu wanted to create an army to fight the legion using the Horde. HOWEVER, his plan backfires as Garrosh, the one he was going to use to lead the orcs against the Legion (After repeating the same process for many dimensions) wants revenge and Azeroth as his own, so he murders him.

Kairozdormu, being an orc is merely because he is in a planet where the only races you could possibly shapeshift to not cause suspicion is a Draenor Orc, Draenei or Arakkoa, making the Orc choice the best as he wanted to hide his identity within the horde.

Kairozdormu is also a Bronze Dragonflight member. This pretty much means that we can see a Kairozdormu in the future before his death (whose death will be avoided due to him finding out that he was killed). Could also turn into an Infinite.