OVA
Description
Chifuyu Orimura teaches as the homeroom instructor for Class 1-1 at the IS Academy and supervises the first-year dormitory. She is the retired world champion from the first Mondo Grosso tournament and Japan's former IS Representative. Her appearance features long black hair, usually in a waist-length low ponytail but shifting to a high ponytail during combat, brown eyes, and a height slightly less than her younger brother Ichika. Her figure draws comparisons to a professional model, with measurements B88 (F-cup Japan/E-cup US), W58, H85. She carries herself with a regal bearing and refined fashion sense, typically wearing formal teaching attire: a white shirt, black business overcoat and skirt, green tie, black stockings, and Mary Jane shoes. For training, she dons a white jogging suit; off-duty, she chooses casual clothes like jeans and tank tops. On specialized missions, such as confronting the Unknown Squad Leader, she utilizes a black full bodysuit. At the beach, she wears a revealing black bikini without hesitation.

Artificially created as Subject 1000 in Project Mosaica, an enhanced human initiative, Chifuyu became its first success before the project's cancellation due to naturally gifted individuals like Tabane Shinonono. She rejected the creators' intentions, especially their plan to eliminate her brother Ichika, who was also a project subject alongside their sister Madoka. Escaping with Ichika, she adopted the "Orimura" surname to hide their origins. She fabricated a story about parental abandonment to shield Ichika from their past. During her school years, she befriended Tabane Shinonono, creator of the IS, a bond extending to their younger siblings. Chifuyu piloted the prototype White Knight IS alongside Tabane during its first demonstration, intercepting missiles aimed at Japan. She later entered the second Mondo Grosso tournament but forfeited the finals to rescue Ichika after his kidnapping by Phantom Task. In exchange for intelligence aiding his rescue, she trained Germany's military forces for one year.

Her personality blends stern professionalism with hidden vulnerability. As an instructor, she enforces strict discipline, physically punishing students for minor infractions and refusing to accommodate Ichika's lack of pre-academy IS knowledge despite enrolling him. She maintains emotional distance, rarely offering praise or showing open affection, particularly toward Ichika, driven by pride and fear of vulnerability, as noted by colleagues like Maya Yamada. At home, she adopts a relaxed, casual demeanor, relying on Ichika for household management and occasionally teasing him. Alcohol lowers her inhibitions, leading to playful or provocative behavior absent professionally. She exhibits intense protectiveness toward Ichika, considering him her sole family. This drives her to enroll him at the IS Academy for safety and prioritize his well-being over duty, abandoning the Mondo Grosso finals to save him. She also mentors emotionally scarred students like Laura Bodewig, encouraging identities beyond military conditioning.

Her relationships feature complex dynamics. With Ichika, she balances maternal protectiveness and unacknowledged dependence. Secretly troubled by the prospect of him acquiring a girlfriend, she paradoxically encourages it. She enjoys his cooking and massages, solicits his fashion opinions—including swimwear choices—and takes smug satisfaction when he prioritizes her. Observers frequently mistake their interactions for a married couple due to their domestic rapport. Regarding her cloned "sister" Madoka, Chifuyu was initially unaware of her existence. Discovering Madoka's Phantom Task affiliation and vengeful motives from perceived abandonment, Chifuyu develops murderous intent after Madoka fatally stabs Ichika. Her childhood friendship with Tabane Shinonono allows unique mutual understanding but deteriorates following Tabane's role in Ichika's near-death experiences. Chifuyu tolerates Tabane's manipulations until critical points, like the Excalibur incident that temporarily killed Ichika. Among students, she is admired as "Brunhilde" but feared for harsh discipline. Female students vying for Ichika's affection eventually perceive her as a romantic rival, especially after she drunkenly declares they must surpass her to "claim" him.

In combat, she displays unwavering confidence from her past as the world's strongest pilot, facing opponents without an IS and mocking adversaries, reflecting enhanced abilities and tactical prowess. However, she harbors profound guilt over deploying students like Laura Bodewig and the Unknown Squad Leader into live combat, acknowledging this violates her ethical duties as an educator. This guilt influences decisions, such as hesitating to return to active duty despite pressure. Her combat legacy includes piloting the White Knight initially, later succeeded by the black knight-themed Kurezakura. This motif extends to Ichika's Byakushiki and Madoka's Kurokishi units. Her signature weapon, the energy blade Yukihira, is eventually inherited by Ichika.

In the "Long Vacation Edition" OVA, she relaxes at a pool in her characteristic black bikini. During a beach outing, her interactions with Ichika and students reinforce her multifaceted persona—combining authority, protectiveness, and subtle rivalry.