Lilith isn't just Morrigan's sister; she is Morrigan as well! Morrigan was born a very special succubus, but Morrigan couldn't control the huge powers she held within: if she were to be left alone, she would destroy herself and the land around her. Therefore, a man named Berial decided to split her powers in half. At the same time her soul was split in half, creating Lilith. Because Morrigan's powers weren't split evenly, Lilith isn't as strong as Morrigan. Though Jedah, who had given Lilith her body, wanted to make her a copy of Morrigan, Lilith child-like innocence imparted a child-like appearance to her own features. Lilith doesn't have that much trouble fighting Fusions, as they cannot penetrate the supernatural defenses of a succubus. Lilith is at Galactus Universe getting ready to join the fight against Galactus.