OVA
Description
Chōun, also known as Shiryū or Sei, first serves Kōsonsan before aligning with Shoku. Her early military history includes fighting alongside Kōsonsan against the Yellow Turbans, where she bravely battles large enemy forces solo, though accumulated corpses later hinder her movements. This act draws Kazuto's attention, who recognizes her potential value.

She assumes the secret identity Kachou Kamen (Butterfly Mask), a tokusatsu-inspired hero. Patrolling in her usual attire with only a simple butterfly mask as disguise, her true identity remains unrecognized by most, though Kazuto and Koumei see through it. As Kachou Kamen, she delivers dramatic speeches, strikes stylized poses, and intervenes in conflicts like rescuing Ryūbi from bandits, reflecting her chuunibyou tendencies. Her persona includes fantastical elements, such as claiming resurrection by an Ultraman-like being. OVAs depict exaggerated transformations where her mask enlarges her size, featuring blinking nipples mimicking Ultraman's Color Timer.

Chōun displays a calm, collected demeanor with a playful, flirtatious streak. She frequently teases characters like Kan'u and Ryūbi with straight-faced, sexually suggestive remarks. Despite apparent knowledge of romantic matters, she initially holds misconceptions, such as believing "pillow games" involve literal pillow fights. Her first intimate experience with Kazuto corrects these misunderstandings, making her one of the most knowledgeable characters on such topics. She harbors a deep obsession with menma, often eating it straight from the jar or using it in unconventional dishes like chocolate fondue dips, occasionally causing conflicts.

In combat, Chōun specializes in graceful, dance-like spearmanship focused on rapid stabbing motions. Her agility and speed allow effective battlefield maneuvering, though she lacks raw strength compared to other generals. She demonstrates proficiency in hand-to-hand combat, marksmanship (throwing masks as projectiles), and acrobatics like balancing on Kan'u's guandao tip. Her physical prowess includes enhanced strength, reflexes, stamina, and skilled horsemanship. She commands troops with strategic flexibility akin to a modern commando unit.

Her character arc involves shifting allegiances: in the Shin Koihime†Musou Gi route, she rescues Kazuto from bandits and later joins Shoku after Kōsonsan's defeat. She forms close bonds within Shoku, often mediating group dynamics through offbeat humor. In Shin Koihime † Eiyuutan, she becomes pregnant with Kazuto's child. Her interactions show protective instincts, especially toward Ryūbi, whom she escorts to safety and whose admiration she cultivates as Kachou Kamen. She engages in playful or provocative situations, like incapacitating Kan'u with a knee move during a mine mission or implying nocturnal activities with Bachou.

Chōun's design features associations with the color white, and her weapon resembles the Spear of Longinus, potentially drawing inspiration from Rei Ayanami. She uniquely refers to Kazuto as "aruji" instead of "goshujin-sama".