Ichika Akimoto is a central character in the first part of the narrative, introduced as a second-year high school student at Metropolitan Misora High School who finds herself thrust into a series of deadly children's games. She is notably the sole survivor of the initial Daruma ga Koronda game from her class, Class C, and her fate becomes deeply intertwined with that of her neighbor and childhood friend, Shun Takahata.

On the surface, Ichika presents a composed and collected personality, functioning effectively as a team player alongside Shun. She is not afraid to speak her mind and a deep bond with Shun is evident, with hints suggesting she may harbor romantic feelings for him. However, this calm exterior is largely a facade that conceals a much darker inner nature. As the games progress, Ichika admits to being a "huge pervert" who derives intense pleasure and a sense of thrill from the life-or-death situations and the constant proximity to death. She feels genuine excitement watching others die or face mortal peril, a secret she is deeply ashamed of and wishes to keep hidden. This craving for excitement means she becomes easily annoyed or disappointed when a game fails to provide that expected adrenaline rush.

Throughout the deadly trials, Ichika's primary motivation shifts from simple survival to a fierce protectiveness over Shun, culminating in a significant sacrifice. Initially, she works with him to overcome challenges, such as helping to put a giant Maneki-neko to sleep and assisting in a jump rope game to obtain a key. Despite her secret enjoyment of the games, she remains a loyal and useful ally. Her ultimate act of devotion occurs during the Judgment Old Maid game, where she sacrifices her own life to give Shun a chance to defeat the entity controlling the games, Kamimaro. In her final moments, she orchestrates a play of cards so that Shun would receive the necessary hand to live on, essentially choosing his life over her own and making a de facto confession of her love for him.

Her key relationships are primarily defined by Shun, but she also has a notable and uneasy dynamic with the volatile Takeru Amaya. While Amaya saves her life on one occasion, pulling her through a doorway to safety, she dislikes his presence in their group. The narrative suggests a brief, non-consensual kiss from Amaya after an early game, further complicating their interactions. Her development is marked by a move from being a somewhat passive participant who works alongside Shun to an active agent who makes a crucial, independent decision to end her own life for his benefit. While one source points out that her character can be seen as fitting a familiar archetype of the female love interest who supports the male protagonist, her hidden perverse nature and final sacrifice add layers of complexity to this role.

Ichika does not possess any superhuman or overtly physical abilities. Her notable strengths lie in her mental resilience, her ability to maintain composure under pressure, and her strategic thinking when working with a partner. Her most significant "ability" is arguably her capacity for deception, as she successfully hides her true, thrill-seeking personality from those around her for a significant period. Her survival through multiple games, including the Daruma ga Koronda, Maneki Neko, tug of war, and an athletic meet, demonstrates her resourcefulness and luck.