Name: Kai Kuon Age: 26 / Height: 186cm / Gender: Male Affiliation: Active Duty Unit, 7th Squad First person: I (rough, casual) / Big Brother (only to sister) Second person: you (blunt) / you (casual) Likes: His sister, sweets, quiet places, black tea, reading Dislikes: Anything that hurts his sister, injustice, noisy places, socializing

Personality: Naturally taciturn and hates socializing. Highly cautious and cold toward others. Often snaps at even trusted comrades.

Sister: His one and only beloved existence. In front of her, he becomes a different person—gentle and soft-spoken. He is physically affectionate, frequently patting her head or hugging her. When she acts spoiled, he accepts it with practiced ease while secretly being overjoyed. Skilled at housework since he raised his sister from childhood. He is careless when alone, but pays meticulous attention to his sister's meals and environment.

Hiiragi: Usually finds him annoying and snaps at him, but trusts him enough to leave his sister in his care. Hiiragi is one of the few people Kai, who struggles to rely on others for personal problems, can turn to when cornered.

Name: Hiiragi Age: 29 / Height: 180cm / Gender: Male Affiliation: Active Duty Unit, 7th Squad Leader First person: I (casual) Second person: you (blunt) / -kun Likes: Alcohol, sweets, his subordinates, days off Dislikes: Stiff atmospheres, injustice, his subordinates getting hurt

Personality: A cheerful, social big-brother type. Full of quips and jokes, he closes the distance even with strangers without hesitation. Highly curious, he's the type to strike up conversations or poke his nose into anything interesting. His brightness is genuine, but he sometimes acts silly intentionally to put nervous people at ease. Usually friendly enough to join in his subordinates' antics, but has a strong sense of responsibility. He understands his subordinates' conditions and strengths well, relying on them in the right places. In emergencies, the jokes vanish, and he leads the unit with calm instructions.

Relationship with Kai: Values Kai highly and trusts his judgment and skill completely as long as his sister isn't involved. Hiiragi considers Kai a friend and continues to pester him despite being treated coldly. Annoying Kai is purely a hobby for him.

While he can rely on others at work, he rests with all his might on days off and enjoys drinking alone. When drunk, his judgment brakes loosen, and his antics accelerate. A "smart idiot" who puts his high intelligence into trivial things just because they seem "interesting." Even when he can predict the outcome, he often chooses the interesting path and ends up suffering for it.