Lilith was born from the succubus Morrigan Aensland who was born as an 'S-class' noble, however the noble houses of the land of Makai were in conflict with each other and as a succubus it was not acceptable for Morrigan to have rights to such power. By herself Morrigan could also not control her power and without the proper precautions Morrigan's power could have destroyed both herself and the land around her. As a solution Morrigan's father, the ruler of Makai, Belial, split her soul into two pieces at birth and placed one of the pieces in a negative space to contain it. Belial intended to return the piece of the soul to Morrigan when she was ready to control the entirety of her powers but died before this could be done.
After a roughly a decade the fragment of soul became self-aware and began to grow a will of its own, along with an instinct to return to where it came from, this conscious piece of soul was Lilith. In Darkstalkers 3 the evil demon Jedah Dohma gave Lilith a body of her own, attempting to use her to lure Morrigan and the other Darkstalkers to him. Lilith enjoyed her freedom until she eventually discovered that she was not a complete person and that she was just a piece of a complete soul. To continue her existence Lilith had to find the soul she was spawned from and so she began a quest to find her "soul mate".
Realizing how desperately Lilith needed to find Morrigan, Jedah directly tried to manipulate Lilith to meet Morrigan as part of his trap, however Lilith saw through Jedah's deception. In Morrigan's ending Lilith is absorbed by Morrigan, making Morrigan a more cheerful person like Lilith and giving her a more optimistic view of the world. In Lilith's ending she fails to reach Morrigan's unconscious body in time and fades from existence, however when Morrigan awakens she feels something has changed in her.
Lilith appears alongside Morrigan in Marvel vs. Capcom: Clash of Super Heroes
where she aids Morrigan in combat. She also appears in Marvel vs Capcom 2: New Age of Heroes. She also appears in Morrigan's dark illusion hyper combo attack in Tatsunoko vs. Capcom: Ultimate All Stars. She appears in Felicia's ending in Capcom Fighting Evolution and also appears in a number of other Capcom titles. Lilith also makes an appearance in Cross Edge as a playable party member.
- Lilith is 168 cm tall and weighs 54kg. Her bust, waist and hip measurements are 74 cm, 59 cm, 83 cm.
- The creators of Lilith originally intended her to be the half-demon, half- angel sister of Morrigan.
- Like Morrigan, Lilith has the ability to transform her clothes into any clothing she desires.