Lucifer Hangyaku no Datenshi, also known as Lucifer, the Rebel Fallen Angel, is a major character in the 'Monster Strike' anime series. Initially an angel, she defies the heavens and is cast out, becoming a fallen angel. As a powerful and charismatic figure, Lucifer leads a group of rebels and aids the protagonists in their battles. Her complex personality, sense of justice, and overwhelming strength make her a central and influential figure throughout the series.