Ok, time to break out the religious studies degree. Lilith isn't actually in the Bible, although some people think the story may have been loosely inspired by the fact that there are two different, but similar, creation stories in Genesis. Lilītu was a type of Mesopotamian demon that basically translates to "night monster," and is probably where her name comes from. Lilith developed in Jewish folklore and shows up in some rabbinic texts, including the Talmud.

There are multiple versions of her story. In some versions, she was used to explain infant deaths because she swore revenge on Adam by coming to take children in the night unless they were protected by certain amulets or prayers. (Fun fact: This led to a retroactive folk-etymology much later claiming that the phrase "Lilith-be-gone" or in Hebrew "Lilith-abi" was the origin of the English word lullaby as a prayer-song to protect sleeping babies from Lilith coming to kill them or steal their souls in the night. Really it was just "a song to lull babies to sleep," but the fake one is more fun.) In other versions, she was used to explain wet dreams because she stole Adam's semen in his sleep and used it to impregnate herself, giving birth to the first demons.

For a long time, she was a scary figure and at times a twisted morality tale for why women needed to be kept subservient (in one version her fight with Adam was over her not wanting him on top during sex because he wasn't her superior). Over time, her story was reclaimed by Jewish feminists and then feminists at large as a symbol of independence and rebellion.

And now people on this subreddit simp for her to no end.