Lilith

Lilith is the wife of Lucifer and the mother of Charlie.

Charlie
Charlie is Lilith's daughter. Their relationship seems to be close evidenced by the pilot, as she gives advice to her, and hints affection towards her daughter when Charlie calls her.

Lucifer
Lucifer is Lilith's husband. It's unknown what their relationship is outside of being married.

Trivia

 * The character of Lilith originates from Abrahamic Mythology where she is a powerful demon who was Adam's first wife and the mother of the Succubi and Incubi.
 * When asked on what Lilith's personality is like (like how does she act, does she act like a goofball like her husband), Hazbin writer Dave Capdevielle said that he wants to answer this question but they can't, and Vivziepop said that she can not talk about Lilith at all.
 * Vivziepop mentioned in her Vivzie Streem #9 live stream that she can't give information on Lilith because it's a very heavy spoiler.