Suzuka Aizawa is a high school student distinguished by pink hair, kemonomimi features, blue eyes, and a slim build. She is Yukito Aizawa's half-sister and shares a close bond with her sister Kotomi. Kotomi's murder during a group vacation profoundly impacts Suzuka. While attempting to maintain composure for Yukito and others, Suzuka struggles to control her emotional distress after the tragedy.

Her personality blends friendliness and a strong work ethic with a tomboyish demeanor and short temper. She pursues photography and swimming as personal interests. During a vacation at a remote mansion, she becomes a target for exploitation by her teacher, Gorou Takamine. He blackmails her using her private diary, threatening disclosure unless she submits to sexual coercion. This forces her into non-consensual relations with Takamine, an experience she finds deeply repulsive but endures to protect her secrets.

As events progress, Suzuka's psychological state deteriorates under the compounded trauma of Kotomi's death and Takamine's ongoing abuse. Her vulnerability is further exploited by other characters, including a maid who manipulates her circumstances. In certain narrative paths, her storyline culminates in tragedy, aligning with the fates of other victims within the mystery.

Her background includes familial connections that later tie into the murder mystery's resolution, particularly through revelations about Yukito's past. In one narrative route, this connection provides deeper context for the events surrounding the killings.