Chōhi Yokutoku, also known by her real name Rin Rin, serves as a central character across the visual novel series, multiple anime seasons, and spin-offs. Her early life was marked by tragedy when bandits killed her parents. Following their deaths, her grandfather took her in, but his subsequent passing left her entirely alone. To combat this isolation, she formed the "Rinrin Bandits," a group of children hiding in the mountains who pranked villagers. This chapter concluded when Kan'u intervened, initially tasked with arresting Chōhi but showing sympathy upon recognizing their shared pasts. After a nighttime battle where Chōhi confessed her loneliness, the two swore a vow of sisterhood while sharing a bed, leading Chōhi to join Kan'u's journey. This intimate setting later caused misunderstandings.

Chōhi exhibits a talkative, cheerful, and tomboyish personality, frequently speaking in third person with the verbal tic "nano-da." Beneath this exuberance lies deep-seated fragility rooted in her traumatic losses. Her fierce loyalty centers on Kan'u, whom she affectionately calls "onee-chan" (big sister), and she displays a strong sibling complex, initially opposing Ryūbi's attempts to become Kan'u’s younger sister. This dynamic resolved with Ryūbi becoming the oldest sister in their trio, securing Chōhi’s position. Naive about romance and sexuality, she creates comedic situations like coining "Operation Houkei-Peeling," unaware of its double meaning. Her emotional vulnerability surfaces during her birthday when she dreams of her deceased parents and breaks down, seeking reassurance from Kazuto (whom she calls "onii-chan") that she won’t be abandoned. She also consults allies like Kouchuu on womanhood, occasionally wearing dresses to appear more feminine.

In combat, Chōhi wields a massive spear with exceptional prowess, favoring powerful slashes over thrusts despite her small stature. Her physical strength allows her to lift heavy objects effortlessly – like a battering ram while weakened by illness – and match Kan'u in battle. However, she lacks technical finesse, making her predictable to skilled opponents. Strategic weaknesses include low intelligence, illiteracy, impatience, and susceptibility to ailments like colds. Beyond direct combat, she demonstrates expertise in trap design from her bandit days and capable horsemanship, though she notably rides a pig in the anime. While her leadership skills are acknowledged, she is often excluded from councils alongside Bachou due to her limitations.

Her relationships feature deep bonds: her devotion to Kan'u includes lap-sleeping, jealousy toward others who aid her, and declarations about their dynamic. She eventually accepts Ryūbi as another sister, calling her "Tōka-neechan." With Kazuto, she shares a sibling-like rapport that evolves into romantic interest as she becomes aware of rivals in his harem. She maintains friendships with characters like Bachou, united by their shared appetite and exclusion from complex planning.

Her role remains consistent across media. In the original visual novel, she joins Kazuto alongside Kan'u, delivering high damage in battles but lacking defensive capabilities. In Shin Koihime†Musou, she appears in all routes: as a core Shoku member, under Ryūbi’s command in the Gi route during the anti-Toutaku campaign, and in the Go route. Spin-offs like Sengoku†Koihime X feature her in Kensuke’s memories, forcing him into grueling marathons. The anime highlights her dedication – such as defending villages while ill – and her gradual acceptance of Ryūbi into their sisterhood by the third season.

Distinctive traits include her tiger-shaped hairpin that changes expressions with her mood, going barefoot, and a large appetite shared with Bachou, Ryofu, and Kyocho. Her backstory and personality draw loose inspiration from the historical Zhang Fei, emphasizing bravery and loyalty while translating his notorious temper into playful stubbornness.