Ritsu, a plant-based being born from her progenitor Riri’s literal division to save Wakaba, serves as the decoy leader and de facto eldest sister among the Sisters. Bound to Midori—a tree generating Green Kemurikusa—she wields its branches and roots for mobility and combat, her own movement restricted by her role as the tree’s devoted guardian. Though she cherishes Midori deeply, guilt plagues her over diverting scarce resources like water to sustain it, doubts soothed only by Rin’s affirmations of its necessity.

Her feline traits—furry ears, a cat-shaped mouth, and a verbal tic ending sentences with “Nyan” or “Nyah”—reflect her inheritance of the First Person’s Hearing. A black, magenta, and white kimono drapes her frame, while exhausted eyes offset her otherwise mature presence, contrasting her sisters’ identical age.

As the group’s emotional anchor, Ritsu exudes calm nurturance, offering moral guidance and tearfully embracing moments of relief, such as discovering Midori’s leaves can mend objects. Lingering guilt over lost siblings like Rinako mirrors Rin’s self-blame, yet she channels this into steadfast resilience, urging unity against adversity.

In battle, she strategically commands Midori’s vines to crush or impale foes, with the ONA adaptation expanding her arsenal to include flight and reshaping the tree into monstrous forms. Unlike her sisters’ initial hostility toward Wakaba, Ritsu greets him with warmth, later supporting Rin’s growing affection for him.

Her journey revolves around reconciling duty with self-worth, climaxing in her acceptance of Midori’s care as vital to survival. Pivotal growth emerges through overcoming resource guilt and affirming her bond with the tree—not merely as obligation, but as a testament to her own stake in their shared future.