Sources: Viz Media, ANN
The angel Alexiel loved God, but she rebelled against Heaven when she saw how disgracefully the other angels were behaving. She was finally captured, and as punishment sent to Earth to live an endless series of tragic lives. She now inhabits the body of a troubled teen, Setsuna Mudo.

Setsuna has a bit of a problem that most teenagers don’t have: He’s in love with his sister Sara. However, things only get worse when he and his sister begin to be attacked by things calling themselves Angels, who claim to be after him because apparently he is a reincarnation of one of the most powerful angels ever. Together, he and his sister get pulled into a war between heaven and hell.
Setsuna's misery mirrors the chaos among the angels, and their combined passions threaten to destroy both Heaven and Earth.

Angel Sanctuary is one of Kaori Yuki's most celebrated works. Among other things, it discusses the morality of incestuous relationships, the nature of God, and other philosophical topics.

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