Lilith is a mini-boss found on floors 1-7 (Don't quote me on this)
Lilith is a gargoyle-like mini-boss that attacks by chasing the player and attacking the player with her staff. She also occasionally tries to shoot the player.
Shoot while being shot by the bullets, and when she charges for you, strafing left is the best way not to get hit.
If you have high enough speed, you can outrun her when she tries to charge you.