Ichika Arima, a 16-year-old high school student with chin-length chestnut hair and luminous pink eyes, balances blunt candor with quiet empathy. Her school uniform and off-campus outfits—soft pastel hues with feminine cuts—reflect her practical yet subtly playful demeanor. A chance encounter at a train station defines her trajectory: after steadying a stranger from a dangerous fall, she impulsively pressed her uneaten lunchbox into his hands upon hearing his empty stomach growl. This man, Ryō Amakusa—older brother of her closest friend, Rio—initially repels her with his relentless teasing and flirtations, which she bluntly labels "creepy" while enforcing firm boundaries. Yet their dynamic shifts through persistent, oddly respectful overtures, thawing her wariness into guarded curiosity. Her friendship with Rio, forged through adjacent desks in first year, thrives on easy rapport and shared humor. Though bemused by Rio’s enthusiastic matchmaking for her brother, Ichika remains skeptical until Ryō’s actions gradually erode her doubts. Meanwhile, classmate Kai Tamaru bonds with her over manga recommendations and anime marathons, though her rejection of his confession—delivered with gentle clarity—preserves their camaraderie. Ryō’s daily gift of a single flower (echoing her name’s "one flower" meaning) and her surname’s uncommon "existence-horse" kanji compound become subtle symbols in their evolving story. Practical details—a revised April 5th birthday, a fondness for stray cats, and her habit of meticulously matching gifts to recipients’ tastes—ground her character. When mutual attraction crystallizes, Ichika insists Ryō wait until her adulthood to formalize their relationship, demanding accountability alongside affection. Their eventual confession at the train station—where their paths first crossed—marks not just romantic closure but a pact for equals to grow together.