Vergil from Devil May Cry (more specifically his DMCV incarnation) can be compared to Sylvanas on many levels.
In his quest for power, Vergil (a half Human, half Demon) split himself into two different beings. The poetry loving sad boi Human V and the single-minded power-obsessed Demon Urizen.
Urizen then planted a Demon tree that fed on the blood of an entire Human city to create a fruit which Urizen ate for ultimate power.
Eventually V and Urizen fuse back into Vergil, and then his twin brother and his son beat him up a bit to work on his issues and he gets a happy ending, sort of. He and his brother Dante end up stuck in the Demon world, but they are no longer trying to kill each other. Now they are just fighting because they are bored. There’s no pizza in the Demon world.
Vergil is even doing things like showing emotion and smiling. It’s cute. It’s wholesome.
But he still ate a whole city worth of people. Nobody seems to mind. Not the characters or the audience.
Sylvanas didn’t split her soul in two by herself. That was done to her. She also destroyed a city for power. Heck, she even had a noble-ish goal, which Vergil did not.
But we seem to really mind Sylvanas’ transgressions for some reason lol
Why is it so? Two vastly different reactions to similar situations?
I think there are four main reasons for that:
1 - We only get to know Sylvanas’ soul was split LONG after we were given reason to hate her. So it feels like an excuse rather than a compelling reason not to blame her. The same can’t be said about Vergil.
2 - Urizen looks nothing like Vergil, He is a vaguely humanoid eyeball monster. It’s hard to associate Urizen’s actions to Vergil because of that. Bad Sylvanas on the other hand looks just like whole Sylvanas but with a different eye glow.
3 - Sylvanas fatigue. The DMC fanbase had been starved of Vergil for years, and he is their most popular character. Sylvanas on the other hand has been very active for a very long time, and people may be just sick and tired of her. It’s hard to sympathize with her when you want her gone.
4 - Night Elves are a playable Race and many people love them. Darnassus was a city you could visit and do stuff in it. A beloved location. Popular among wow players. Redgrave City was made up on the spot and nobody cared.
I think that’s it 
