|Novel||Part I: Chapter 01|
|Anime||Episode 01: The Season of New Leaves|
Reiko Amano (天野 麗子 Amano Reiko) is the sixth member of Group One in the beginning of the story. She is the first student to be killed by a Tainted Cat due to her weak performance in class.
Reiko appears to have short dark brown hair that reaches her shoulders and has purple eyes. She wears the same uniform as the other female students, which consists of a beige vest with a radiant orchid shaded seam, and a purple bow tied over the midsection. Additionally, she wears a skirt in the same color as the seam, as well as fitting boots combined with a large part of beige and black stockings beneath. On each side of her short sleeves are yellow fringe accessories with tiny turquoise pearls on them. On both shoulders, there are overlapping parts of the top clothing.
Reiko was born in Gold  and became a member of Group One upon having her cantus activated and entering Sage Academy. She is considered extremely clumsy, as well as slow with her cantus where she ends up frustrating the people in her group because of her poor abilities and is seen to be excluded by them later (through Satoru Asahina not asking her to walk home with them), though not particularly because of ill intent (Satoru claims he did it as to not embarrass her). She is eventually killed by one of the Tainted Cats while walking home late after school, due to high chances of her turning into a Karma Demon if she was to continue living.
Reiko seems to be rather insecure, fairly quiet, and apologizes often for her mistakes. Due to the pressures put on students in Sage Academy to excel, it seems likely that she was affected by that pressure for her weak cantus which held everyone else in her group back.
- Group One: In the manga, Reiko, Saki Watanabe and Maria Akizuki are seen to be close friends, who occasionally show their affection to each other by sharing physical intimacy, which is common between children and teenagers of the same sex. It is also seen that she has known everyone (except Mamoru Itou) since the beginning of Harmony School.
- The name Reiko means "beautiful, lovely" (麗) (rei) and "child" (子) (ko).
- Reiko's surname Amano means "heaven, sky" (天) (ama) and "field, wilderness" (野) (no).
- Unlike the majority of the members of Group One, Reiko went to Morality School, not Harmony School . This aspect is changed in the manga as Reiko seems to have known the majority of the group from Harmony School before entering Sage Academy.
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