So she, daughter of Mephisto, had kids with Inarius, the angel, who together founded Sanctuary. They created it so there could be peace, away from the angel and demon perma-war they wanted nothing to do with anymore. They created the first nephalem.
Angels and demons alike were threatened by the power of the nephalem, and considered their entire being, a blasphemy. Inarius was indecisive about what to do with them. Many called for the genocide of the nephalem, but he wasn’t sure and went to reflect on the matter. Lilith, on the other hand, said “SCREW THAT NOISE” about her kids being all genocided. She started killing off those calling for the genocide of her kids, the nephalem, angel or demon – didn’t matter.
Inarius came back from his “vacation to reflect on the matter of killing all his kids” to find that Lilith killed all those calling for their deaths. He banished her to the void, since he had made a vow to never harm her. Meanwhile, humanity (who I guess came from the nephalem) started summoning demons so the Prime Evils became aware of Sanctuary.
Lilith escaped the void and was hellbent on revenge. But I mean, it seems kind of just. She was only trying to protect her kids from all being murdered. She was peaceful before that. But anyway, she started gathering her own following of nephelem. Inarius ends up banishing her to the void again tho.
Mephisto ended up torturing Inarius in hell, twisting his body, ripping off his eyelids with mirrors everywhere so he had to look at it all day and night. I mean he was probably pretty pissed about him and his daughter and all. But since the black soulstone was destroyed, he had no jailer anymore and escaped or was released. And he doesn’t care about his vow to never harm Lilith this time around.
Now D4 happens. Lilith is apparently summoned back into the mortal world again by an unknown person in the cinematic. Likely a cultist from her first time back before she was banished a second time. I think both of them have cults or something.
But it kind of seems like Lilith is the one in the right here. She just wanted to be left alone and protected her kids from being killed. What’s so wrong about that? Everyone else seems like the baddie.