Lilith

Lilith is the sister of Beelzebub and Belphegor. She died during the Great Celestial War due to attacks from the opposing angels and fell down from the Celestial Realm. Beelzebub claims to be disturbed and saddened by the fact that he was unable to save both of his siblings during the war and was only able to shelter Belphegor during the time of the attack.