Lilith was a mortal woman that Cam was to marry in the past. She was in love with him, and ignored all the bad things that her family and everyone else said about him until the day of their wedding when Cam declared that he could not marry in a church.This was actually due to his status as a fallen angel, but Lilith was not aware of that, so she left him. Before she did, she angrily said that she wished that she would have hundreds of granddaughters, so that there would always be a woman on this world to loathe him. Her wish later came true, apparently; Luce met a Nephilim girl named Lilith in Shoreline that was later revealed to be the "descendant" of the original Lilith, whom she resembled. It's also hinted that Cam knows the new Lilith, as it's shown on Lauren Kate's official website that he pressed charges against her.
Briefly in Passion, we meet Lilith in a past life. It is revealed she was Cam's lover and that they were supposed to marry. But since Cam couldn't enter the chapel (since he's a Fallen Angel), she left him and later killed herself.
Unforgiven surrounds itself with Cam and Lilith's story. Lilith is revealed to have many lives, as Lucinda did, but each created by Lucifer and meant to be a personal Hell - Except for music. Lilith in her current life lives in Crossroads, Texas and has school 7 days a week. She has terrible luck with almost everything except her music, which she excels at. When upon meeting Cam Briel, she finds herself inexplicably hating him, but also mysteriously intrigued by him. In an effort to win Lilith's favor, Cam enrolls in her High School and she, Cam, (and a few other isolated kids in her school, Jean and Luis), form a band called 'Revenge'.
The Legend of Lilith
Daniel mentioned in Passion that Lilith was the first wife of Adam to Miles and Shelby. This is according to some Jewish folktale. After she was created, she left Adam and flies around the world, cursing people. She is also called "The Howling One."
Lilith is described as being extremely gorgeous, she is tall, has long armed red fire color hair going up your narrow waist and icy blue eyes. She is thin, with a skin that is pale in Unforgiven and Passion, has a tanned skin, due to the scorching heat of Jerusalem, yet her skin is still very soft. She has a few freckles on his shoulders and around his nose. In Passion, Miles is mesmerized by her great beauty.