We meet Karou, a beautiful blue-haired orphan girl who lives alone, attends art school, and disappears on mysterious errands. Her only human friends are Zuzana, a tiny, fierce girl and Mik, Zuzana's boyfriend. Although they express concern about Karou, they have learned that there are certain things she won't (or can't) share. They provide both comedy and comfort in a trilogy that could have been dark and desperate instead of an inspiring and rewarding read.
Karou appears to consort with monsters and have an angel for an enemy. Akiva, the angel hunting her, appears to be haunted by his past and lost love. He is tortured by his past and a desire for revenge, she is determined to save her demon friends. It soon becomes apparent that the demons are not entirely demonic nor are the angels completely angelic. They are two separate races who despise one another. Karou and Akiva's relationship is the source of unending heartbreak in the past and blossoming hope for a future.
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Throughout the trilogy, the author takes the reader on a journey that destroys assumptions and opens the mind. This is not merely a love story between two otherworldly creatures. This trilogy is about longing, forgiveness, understanding and redemption. We come away believing in the world that the author has created. A highly recommended teen read that adults will love.