Something is not quite right.
"Only Beasts are above deceit" - Rexxar
Nobody talking about Nathanos?
The lich king in any shape or form is unfit to rule the forsaken, since in that moment they cease to be forsaken and just become regular scourge.
If this hypothetical were to pass--where Sylvanas betrays the Forsaken and the Horde--it's far more likely Nathanos would step up to lead them in her place, given the recent short story explaining how he went from rotting and desiccated to the ingame Legion model showed cracks already beginning to appear in their relationship.
Be seeing you guys on Bloodsail Buccaneers NA!
Except there's Nathanos, so.
They always told me I would miss my family... but I never miss from close range.