Arisa Yuki transferred into Makoto Yūki's class at Mochizuki Academy shortly before its closure. She possesses dark blue hair reaching her back, typically adorned with a white and pink cat-like headband, light blue eyes, and snow-like pale skin. Her delicate features and reserved demeanor created an unapproachable aura, though she remained oblivious to this perception. Standing 145 cm tall with a slender build, she moved with a quiet intensity. Her personality is weak, quiet, and reserved. Social interactions proved challenging after a long-term hospitalization severed connections with peers. Even after recovery, attempts at conversation caused extreme nervousness, reducing her speech to near-whispers audible only at close range. Overwhelming anxiety could escalate into panic, leading her to flee. Books became her refuge, and she frequently spent breaks reading alone by classroom windows. Before hospitalization, she relied on Makoto as a trusted friend. Upon discharge, she discovered he had grown cold and forgotten their past connection. This abandonment fostered resentment, and she resolved not to forgive him until he offered a sincere apology. Despite this, Makoto's smile retained the power to dissolve her anger instantly. She longed to be acknowledged as a childhood friend within Makoto's core group, sharing the bond he had with Nono, Iori, and Matsuri. This desire stemmed from admiration for their closeness and profound loneliness. Her background includes an inability to swim, a vulnerability Makoto once attempted to help her overcome. This shared experience likely contributed to her developing feelings for him. Her story centers on her tentative integration into the group searching for their buried time capsule and her quiet hope for acceptance within their circle.