TV-Series
Description
Kotori Itsuka is the adopted younger sister of the protagonist, Shido Itsuka, and a middle school student. Beneath this familial role, she holds the crucial position of commander for the airship Fraxinus, an asset of the organization Ratatoskr, which seeks to resolve conflicts with otherworldly beings known as Spirits through peaceful means.

Kotori is a girl of small stature, standing 145 cm tall, with long, light coral-colored hair that she typically wears in twintails and red eyes. A distinctive feature is the ahoge, or antenna-like hair, that always sticks out from the top of her head. She is almost always seen with a lollipop in her mouth. Her appearance is notably marked by the color of the ribbons she uses to tie her hair. When wearing white ribbons, she usually dresses in her school uniform. When wearing black ribbons, her attire changes to a red coat over a white uniform, befitting her role as commander.

Kotori’s personality is closely tied to the color of her hair ribbons, representing two distinct sides of her character. While wearing white ribbons, she embodies what is referred to as her weak self, acting as a delicate, affectionate, and somewhat dependent little sister who calls Shido onii-chan. According to Reine, a fellow Ratatoskr member, this is the side of Kotori that can honestly express her true feelings. In contrast, when she wears black ribbons, she switches to commander mode. In this state, she becomes her strong self: a charismatic, sharp-tongued, and occasionally cynical leader who commands the Fraxinus with authority and can be strict with Shido, often for his own safety. This shift is not a split personality but a conscious switch to separate her personal life from her professional responsibilities.

Her motivations are deeply rooted in her past and her relationship with Shido. Five years before the main events of the story, a young and lonely Kotori was approached by a mysterious, mosaic-cloaked being later given the codename Phantom. Exploiting her fear that her brother would leave her, this being offered her a crystal that granted her the powers of a Spirit, transforming her into a being of fire codenamed Efreet. In her失控 state, Shido was injured trying to help her. The mysterious entity told Kotori that the only way to save her brother was to kiss him. She did so, and Shido absorbed and sealed her powers, an act that also gave him his unique regenerative abilities. Following this incident, both siblings had their memories of the event suppressed. Kotori, despite being only eight years old, was later recruited by Ratatoskr and became the commander of the Fraxinus, a position she holds to protect Shido and ensure the peaceful coexistence of Spirits and humans. She carries the heavy burden of knowing that Shido has inherited her former power and is prepared to take drastic measures if he ever loses control.

In the story, Kotori serves as Shido’s primary advisor and mission control during his dates with other Spirits. From the bridge of the Fraxinus, she analyzes situations, provides tactical guidance, and evaluates the success of his attempts to make the Spirits fall for him and seal their powers. Her role is essential to Ratatoskr’s strategy, and she acts as a central figure in coordinating the organization's efforts. She maintains key relationships with the other Spirits, especially Tohka Yatogami and Yoshino, with whom she frequently interacts. She is notably wary of the dangerous Spirit Kurumi Tokisaki, even attempting to eliminate her as a threat, which contrasts with Ratatoskr’s generally peaceful approach.

Kotori’s character development is centered on the reconciliation of her dual identities and the acceptance of her past. For most of the series, she keeps her own Spirit powers sealed within Shido. However, when a desperate situation arises, she can choose to take her power back, fully manifesting as the Spirit Efreet. In this form, she wears an astral dress called Elohim Gibor, a white, kimono-like robe with two horns protruding from her head. She wields the angel Camael, a massive halberd made of flames that can transform into a powerful cannon known as Megiddo, capable of firing devastating energy beams. Her most notable ability is a powerful form of regeneration that can heal even fatal wounds almost instantly, as long as she has sufficient spiritual power. While extremely powerful, her abilities come with a significant risk. Prolonged use of her Spirit form causes her to lose control to a berserker-like third personality, turning her into an aggressive, merciless, and sadistic combatant who craves battle and destruction. For this reason, she views using her full Spirit powers as an absolute last resort.