Chitose Shirakawa, a high school student with auburn hair and red eyes born on May 5, serves as a supporting character and is the girlfriend of Itsuki Akazawa, who affectionately calls her "Chii." Her personality radiates active, light-hearted, and boisterous energy, marked by extreme honesty in her expressions and actions. This outgoing nature helps her befriend classmates easily and maintain popularity. She displays strong devotion to Itsuki, often appearing clingy in their relationship, which occasionally draws humorous objections from peers like Amane Fujimiya due to her loud behavior.

Chitose plays a pivotal role in helping Mahiru Shiina lower emotional barriers and reveal her true self. Through persistent, genuine interactions, she encourages Mahiru to embrace her fondness for cute things and express her energetic side, aiding Mahiru’s personal growth. Beyond this, Chitose actively involves herself in friends' lives, including Amane’s, offering encouragement alongside Itsuki despite Amane’s initial reluctance toward her exuberance. She strives to strengthen bonds within their group and demonstrates perceptiveness about others' emotions.

Formerly the track and field club’s ace, Chitose resigned due to internal conflicts shortly before dating Itsuki, hinting at competitive and determined traits. She cooks competently when not adding prank elements to dishes, revealing a playful side. Though generally supportive, she occasionally exhibits light jealousy—particularly regarding Mahiru and Amane’s evolving relationship—and often teases Amane about it, showcasing her mischievous yet well-intentioned approach.

Her development across the series reflects growing emotional maturity in navigating relationships with Itsuki and friends. Her surname Shirakawa means "white river" (from "shira" for white and "kawa" for river), while her given name Chitose combines "chi" (thousand) and "tose" (year-end, age), signifying "thousand years" or "millennium."