Blizzard seems to keep the "Kil'Jaeden is not really loyal to Sargeras" thing from Sunwell Plateau, it seems. Also, this is just more proof that he is going to die forever, considering it says "final" battle.
Also, Quest 2 of the Mage Order Hall Campaign:
You go to Akazamzarak, who is currently trying to make his own Elementals similiar to the one Khadgar uses (like the one from the long quest in Shattrath).
You go to Dalaran, use an ability on players (and players only), and an elemental gets summoned that follows them for like 5 minutes.
As a thank for your help, he wants to teach you his "Hat Trick" aka how to pull rabbit out of his hats.
When you try to do it though, something bad happens:
You literally just pull out a spine.
So you go inside his hat, into the "Bunny Dimension" to find out what is wrong.
So it turns out that somehow that there's a wolf inside. You kill it, go back out, and you get Akazamzarak as a follower.