In Game Storyline question (OOC)

[theshard]

So on the way to work this morning, my roommate asked me "In the new patch, which faction is fighting Illidan?"

My response, "Both, I believe."

He proceeded to contradict the logic saying that at the end of Warcraft III, Illidan was the leader of the blood elves. I never finished W III so I can't say but according to him there was a big thing at the end with the blood elves, naga and possible some others all doing whatever it was they were doing in the Outlands.

I have read a few of the novels and played most of Warcraft III and the Frozen Throne. I also know some of the history from what I have read here and there. But what happened between Warcraft III and current storyline?

Sorry if this is the wrong place for this but it seemed the most suited.

[Icefrost]

Illidan, Kael(blood elf) and Vashj (naga) tried to destroy the frozen throne at the end of W3. In that mission you play as Arthas who then comes just in time to stop them and beats up Illidan before going up to take the throne for himself.
Sometime after that, Illidan and his comrades had to go back to outland where they would hide from Kil'Jaeden. As far as I know, the blood elves you get to play in WoW are just trying to get to Kael in outland, but I don't know why they'd end up fighting him. (he is a raidboss after all)
Someone please fill in the details for me.

[Shanda]

Theres stated in a few quests that Kael has betrayed Illidan and sided with the burning legion. To..basicly do what he does in Netherstorm and control the world bla bla as usual. This of course made some bloodelfs leave Kael (the Scryers) And they end up telling you that hes evul and needs to get poked..hard.

[Leord]

The rest of the Blood elves have also left Kael because of his shady decision. Most of the Belfs are unaware of what have actually happened, and are just happy that some of their beloved Silvermoon City is rebuilt.

Both Belfs and everyone else fights Kael in raiding in (current) late endgame.