Chisaki is a fair-skinned and attractive young woman, often considered one of the more mature-looking members of her group. She has long dark auburn hair that reaches past her waist, typically tied in twin braids during her time in Shioshishio. After the time skip, she changes her hairstyle, wearing it loose or partially tied, reflecting her growth and evolving identity.

Chisaki has expressive violet eyes and a slender yet curvaceous figure, which she is somewhat self-conscious about, especially when compared to her more petite friends. Her sense of modesty and occasional shyness contribute to her discomfort about her body, though this becomes less pronounced as she matures.

She is often seen in the traditional Shioshishio school uniform prior to the time skip. After relocating to the surface, she adopts a more casual and modern wardrobe suited for her nursing studies, often wearing cardigans, skirts, and other simple but elegant clothing.

Chisaki is a warm-hearted and thoughtful individual known for her gentle nature and emotional maturity. She deeply values the bonds she shares with her friends and often acts as the emotional anchor of the group. One of her greatest fears is change particularly the idea that growing up or evolving as individuals might disrupt the close-knit dynamic she shares with her childhood friends. This aversion to change stems from her desire to preserve their relationships exactly as they were.

Despite her calm and composed exterior, Chisaki is not immune to emotional outbursts. When deeply provoked or overwhelmed, she can become noticeably upset, especially in situations involving those she cares about most, such as Manaka or Hikari. Kaname once commented that, despite her usual serenity, she could be “crazy and emotional” when it came to matters of the heart.

Chisaki is also known for her introspective nature and tendency to hide her true feelings, often putting others’ happiness before her own. As the story progresses, she gradually learns to confront and accept her own emotions, allowing herself to grow more honest and open with those around her.

During her childhood in Shioshishio, Chisaki shared a close bond with her friends Manaka Mukaido, Hikari Sakishima, and Kaname Isaki. On one occasion, when she and Manaka wandered to the outskirts of the village into the open sea to search for coral, the two became lost. Eventually, they were found and rescued by Hikari. In that moment, the simple act of Hikari holding her hand left a strong impression on Chisaki, marking the beginning of her romantic feelings for him. This childhood memory remained significant to her as their relationships continued to evolve.

Tsumugu Kihara
Initially, Chisaki viewed Tsumugu with apprehension due to Manaka Mukaido’s apparent infatuation with him, fearing that such feelings would disrupt the balance of their friendship group. Over time, however, her opinion of him changed as they grew closer through shared experiences. Their bond deepened significantly following the events of the Maiden Sacrifice. When Tsumugu’s boat was overturned by a large wave caused by the Sea God, Chisaki dove into the sea in a desperate attempt to save him. With the help of Kaname Isaki, she managed to rescue him, cradling him in her arms once he was safe, symbolizing the emotional shift in their relationship.

Manaka Mukaido
Chisaki and Manaka have been best friends since childhood, often seen together throughout their early years. Chisaki has always been protective of Manaka and hesitant about change, particularly when it involved the dynamics of their friend group. Although she deeply values their friendship, Chisaki often struggled with conflicting emotions due to her feelings for Hikari, whom Manaka also loved. She experienced guilt and frustration, especially when Manaka seemed to understand and support Hikari more than she could. Chisaki initially rejected Tsumugu’s feelings, believing that Manaka loved him, but later learns that Manaka had actually harbored feelings for Hikari all along. This revelation helps Chisaki reconcile her emotions and eases the tension she felt about standing in the way of their relationship.

Hikari Sakishima
Chisaki has long harbored romantic feelings for Hikari, one of her childhood friends. She admired his courage and his ability to influence others, but also felt helpless whenever she was unable to support him like Manaka could. This left her feeling inadequate and conflicted. Despite her strong feelings, Hikari never returned them, seeing her more as a sibling than a romantic interest. Though Chisaki considered confessing her love, she ultimately chose not to, believing that revealing her feelings would disrupt their close friendship. Eventually, she acknowledged that Manaka held a special place in Hikari’s heart, and came to terms with her unrequited love. Hikari, unaware of the depth of Chisaki’s feelings, never directly addressed them, and the topic remained unspoken between them.