TV-Series
Description
Kūgeru is a special individual among the Tesseractors, beings born from human malice and desire that bring strange phenomena to Kamitsubaki City. Her origins are highly unusual, as she was born under rare circumstances that set her apart from ordinary Tesseractors. Her true form is partially human in appearance, blending human and non-human traits, making her distinct from others of her kind. Her appearance in human form features short gray hair and blue eyes.

Kūgeru possesses the extraordinary ability to manipulate lightning at will, a power that is described as exceptional and formidable in its scale. This ability sets her up as a significant force in conflicts.

Her personality is predominantly taciturn, strict, and introspective. She maintains a stern and rigid demeanor toward most others, holding everyone to high standards. However, a notable exception exists in her relationship with Koko Rinne, toward whom she is somewhat softer and more lenient, suggesting a deep and personal bond between them.

In the story, Kūgeru serves as a supporting antagonist or obstacle. She makes a pivotal move by killing the Reconstruction Division Chief, a critical figure responsible for the city's anti-Tesseractor defenses and information control. This act sends the city into chaos, cripples the defensive systems, and causes a severe psychological breakdown for the protagonist Kafu Morisaki, who witnesses the event. Following the killing, Kūgeru escapes and remains missing for a time, with her motivations initially unclear. Koko Rinne, who previously had been the one closest to her and had lost her memories, is shown to have a history of friendship with Kūgeru, adding layers of personal conflict and tragedy to the betrayal.

Kūgeru's development is tied to her mysterious background and her violent turn against the forces protecting the city. Her role shifts from an enigmatic ally to a direct threat whose actions have far-reaching consequences for the city's stability and the emotional state of the main characters. Her unique origin and specific bond with Koko Rinne suggest a deeper personal motivation for her actions, though the full extent of her character arc is rooted in the conflict between her nature as a Tesseractor and any personal loyalties she may hold.