Lilith is a very high-ranking demon under Asmodeus, the Prince of Lust.
After the planet Ludus was shaped, when the first few gridmasks settled on a then miniscule island now known as the main continent Okto-Gredile, Lilith was brought forth by Chaos. After seducing a man known as Karim, she gave birth to her three children, Shedim, Rauchin and Lilin, the progenitors of the three primal batches of dark magic users (Warlocks, Necromancers and the more obscure Sanguine Casters).
Prior to the events of WiR, when Twilight opened her first highly unstable Hell portal, she and a great amount of other infernal creatures escaped into the physical world, dooming the timeline even further. Nearly all of the original inhabitants are killed in this event.
After the Ones Who Went Back traveled backwards through time, emporer Jast DeCurro, being the greatest follower of Gaia still alive, performed the mythical act of the Second Great Banishment. The world was rid of demons once again, this time all sent to the Gray Zone. Lilith is, along with almost all of demonkind, eradicated in this doomed timeline.
In another timeline entirely, where all the planets of the Separ Dimension folded into the Extraspacial Incubator, Lilith was again free to roam a different realm. Here, she resided in a dungeon known as Lascave Depths.