From Diablo Wiki
Lilith, also known as the 'Mother of Misery,' 'Queen of the Succubi,' 'Mother of Deceit,' and 'Mistress of Betrayal,' is a powerful demon. She is coeval with the Lesser Evils, but not counted as one. She is the daughter of Mephisto, sister of Lucion, and mother of Linarian and Andariel.
Lilith's true form is that of a tall, humanoid Demoness. Her complexion is dark green and black. Four long, jointed limbs extend from her back and reach in front of her, two on each side, each with a large spike at the end. Her hands each have four fingers ending in claws. She has large breasts and a feminine face with a mouth full of fangs, and hooves rather than human feet.
Lilith is a manipulator and seductress, attractive even in her demonic form. She has always aimed to receive affection from powerful beings, using them as pawns to further her own goals. Such examples include Inarius and Uldyssian.
 Sanctuary and Nephalem
She was part of the rogue demons and angels who created Sanctuary. Her mating with Inarius resulted in the Nephalem cross between angel and demonkind, a very powerful race of beings who later became the dominant race on Sanctuary, the humans.
However, she desired to use these powerful Nephalem as an army to take on both the Burning Hells as well as the High Heavens and with that came into conflict with Inarius who wanted to undo their creation. Lilith prevented this by killing many of the rogue demons and angels, but ended with her being banished from Sanctuary.
 The Sin War
Lilith later returned and tried once more to use the Nephalem against her percieved opponents, weakening the Worldstone (that prevents Nephalem from developing their powers) and helped awaken Uldyssian's hidden Nephalem powers. She tried to seduce him into creating the army of Nephalem she wanted, but ultimately failed as Uldyssian used his power against her.
 Pandemonium Story
She masterminded the revival of Diablo by manifesting herself in the mortal realm and performing a ritual of Dark Summoning. This ritual, long thought to be impossible by the most powerful mortal wizards, allowed Lilith to link with Diablo across realms, strengthening him until he was finally able to once again reincarnate himself in the mortal plane.
Rage and a deep yearning for revenge boiled within the eyes of the Lord of Terror, and together he and Lilith resurrected the two remaining Prime Evils as well as Duriel and Izual, two of their strongest agents.
Diablo announced his grand plan - the Three were finally strong enough to spread Sanctuary. Lilith could have easily conducted an assault on her own, but because she had been left severely weakened by the Dark Summoning ritual, she agreed to aid the Prime Evils and command some of their remaining forces.throughout
 Diablo II Pandemonium Event
To read up on Lilith's stats and the Pandemonium event, see the articles on the:
|Characters & NPCs Import. Chars Rumoured Diablo 3 NPCs Diablo 2 NPCs Diablo 1 NPCs Minor A-K Minor L-Z Fanmade|
|Diablo III's Possible NPCs|
|NPCs of Diablo II||
Achilios - Adria - Akara - Albord - Aldric Jitan - Alkor - Anya - Arkaine - Asheara - Assur - Atma - Augustus Malevolyn - Baerna - Banagar - Benjin - Brek - Buyard Cholik - Camylle - Celestia - Cornelius - Darrick Lang - Diomedes - Drognan - Edgewulf - Elora - Elzix - Emilye - Fara - Farnham - Fautzin - Galeona - Garda - Gheed - Gillian - Gorst - Greiz - Griswold - Guthwulf - Hagan - Halbu - Hanos Jeronnan - Hargo - Hays - Hratli - Hrothwulf - Humbart Wessel - Hunfrith - Hyram - Icharion - Jace - Jamella - Jerhyn - Jodas - Juris Khan - Justinian IV - Kabraxis - Kara Nightshadow - Karybdus - Kashya - Kentril Dumon - Kethryes - Korlic - Kreghn - Ku Y'leh
Lam Esen - Larzuk - Linarian - Lysander - Malah - Mat Hu-Ring - Meshif - Mirakodus - Mordecai - Natalya - Nefriti - Nellia - Nihlathak - Nor Tiraj - Norrec Vizharan - Ogden - Ord Rekar - Orlif - Ormus - Oskal - Palashia - Pepin - Qarak - Qual-Kehk - Riordan Nesardo - Sadun Tryst - Salene Nesardo - Sardak - Sarnakyle - Septumos - Simon - Talic - Taramis Volken - Tilgar - Tobio - Toko - Tylwulf - Vischar Orous - Warriv - Wirt - Wulfgar - Xazax - Zagraal - Zayl - Zorea