One of the Seven Satans, "Wrath", she is Lucifer's first wife and mother of many demons and Abaddon. Barbelo was once an angel in Heaven named Baru. She watched over Lucifer and Michael when Lucifer still resided in Heaven. During the First Great War, she forced Michael to take her to the battlefield so she could see the fight for herself and that it was really Lucifer leading the army. When Michael went to attack Lucifer, she got in the way and was cut down by Michael's sword. After the fight, Lucifer saved her life and made her the Satan of Wrath.
However, she retains memories of her life as an angel, as well as a scar where Michael had injured her. Initially, Michael did not know that she survived his blow. But as Lucifer started dropping hints to him, Michael finally figured out who she was. He then struck her down a second time, as she was holding onto Setsuna's leg to prevent him from escaping.