He suddenly appears upon Azeroth, everyone gasps at his return…you watch as the mangled dead body of Illidan falls from his hand to the ground.
(Incoming new expansion, this time not the burning legion but he has corrupted the Titans and their creations are what we are battling, we need to travel to the Titan “Homeworld” to cleanse or destroy them)
Maybe before Illidan died at Sargeras’ hands he cast a spell or somehow weakened him a great deal so his whole mission is to regain his power and continue fighting us.
Its more likely that Sargeras and the legion where the only thing holding back the old God’s (as far as the old God’s are concerned, we can and will whup 'em).
Likely, Voljin was corrupted by the old God’s, particularly at the end, and that’s why he appointed Sylvannas, knowing she would go genocidal given the chance and weaken both horde and alliance.
Next expansion after BFA will be Fighting the Old God’s, Battle for Sanity(This is a working title)
Hey, look, he still has that plaster on his left pinky when Method tried to fight him.
If all of us gang up we might be able to chop it off and he’ll need to run to his bathroom to get bandages.
Vol’jin was killed by the legion. He was infected with fel. If anything KJ, Sargeras, or another higher up pretended to be his Loa and told him to pass the torch to Sylvanas. She herself is more likely an agent of the legion than of the void because of this. Remember that the scourge are all a byproduct of the legion.
And remember how the Lich king and his scourge was practically unphased by the Saronite that ICC was made of.
The only thing I can imagine if they decided to reintroduce Sargeras (which I think he should had a bigger part in Legion) is that with Azeroth (now a full grown titan) we get the other titans including Sargeras to battle the Void Lords and the Naaru cause they’re also know to be “Join our prophecy freely or be enslaved to it” mentality.
You character wakes up in sweat in his Garrison. The events of Legion and Battle for Azeroth was a dream. Next patch is 6.3, opens a new quest zone and raid in Faralon. Having nothing to do (because it’s WoD), your character goes back to sleep.
Blizzard announces patch 7.0 about the return of the Burning Legion to Azeroth.