Itsuka Kotori

Shido's foster sister who was a human that gained the power of a Spirit five years prior to the start of the main story and thus, saved by Shido at that time. There is no record of how she obtained her Spirit powers, and she herself cannot remember; she does not know why both Shido's and her own memories are vague or missing at that crucial point, though she suspects someone may have tried to erase those memories. However, she isn't able to handle her Spirit powers long before she loses control and is overcome by a powerful need to destroy and kill. When her Spirit powers overwhelm her, she retains no memories of any events that transpire during that time. She temporarily takes back her powers from Shido to save him from Kurumi with her power being sealed by Shido once more later on. At the second sealing, she and Shido both regain their lost memories of the first sealing: an entity called "Phantom" granted her her Spirit powers when she was left alone at home and crying (with which she destroyed everything around her and nearly killed Shido), told her to kiss Shido if she wanted him to live (which was how Kotori knew about the method to seal a Spirit's powers, and also the ability to heal from serious injuries that Shido got from her), and afterwards stripped them of their memories of its existence, as well as Shido's memories of the entire incident. This memory also disproves Origami's belief that Kotori was the one who killed her parents, and that it was another Spirit that did it.

She has red hair, often in twin ponytails, and her eyes are red. She is almost always shown with a Chupa Chups lollipop in her mouth. She displays two very different characters, bordering on split personality. When she wears white ribbons in her hair, she is completely relaxed and peaceful and shows an immature, spoiled character that's always clinging to her brother. When on theFraxinus or dealing with major situations, she switches to black ribbons taking on an arrogant, superior attitude to everyone including Shido, but nevertheless still cares deeply for him as shown on many occasions. This difference in character is revealed in volume 4 to be due to Shido giving her black ribbons as a present for her ninth birthday after sealing her powers, and telling her to be strong as long as she wears them. However she is extremely weak to horror-related things, and reacts strongly to them regardless of character. She also shows evidence of concealed romantic interest, such as when she declared to Mana that a foster sister is better than a full sister because full siblings can't marry, then gets flustered when she realizes she said it in front of everyone else.

Her Angel is Camael, a halberd that is capable of changing shape to a cannon that extends to her right elbow. She also has the ability to recover from severe injuries, which Shido uses when her powers are sealed inside him. Her Astral Dress, Elohim Gibor, is a kimono which mainly consists of the colours pink and cream. In her Spirit form she also has horns growing on her head, with her black ribbons tied on them. Her AST codename is Efreet.