Kenta Akamatsu is a student in Class 2-1 at Kure Academy who becomes a participant in the deadly King's Game. He is characterized by his straightforward and earnest personality, often acting as a hot-blooded individual who is not afraid to speak his mind. His primary motivation throughout the ordeal is to survive alongside his classmates, and he demonstrates a willingness to actively challenge the rules of the game rather than passively accept its cruel commands.

In the story, Kenta serves as a supportive ally to the protagonist, Nobuaki Kanazawa. Unlike some other students who turn against Nobuaki out of fear or desperation, Kenta remains a steadfast companion, choosing to work with him and fellow classmate Mizuki Yuuki to uncover the mysteries of the King's Game, including a journey to the isolated Yonaki Village to investigate its origins. His role is that of a loyal friend who believes in cooperation over sacrifice, directly confronting Nobuaki when he perceives his actions as becoming too calculating or callous for the sake of survival. When Nobuaki coldly suggests a strategy that would involve using other classmates as a means to an end, Kenta openly calls out this harsh disregard for life, highlighting his own moral compass.

A key relationship for Kenta is his budding romance with Mizuki Yuuki. Their bond, which has been present since the beginning of the class's nightmare, becomes a central focus of his personal story. As they face impossible orders from the King, Kenta and Mizuki are forced to confront their feelings for each other, culminating in a desperate love confession as they try to navigate a command to send death threats to their peers. Despite their efforts to find a solution and their mutual affection, both ultimately fall victim to the game's unforgiving rules on a technicality, making their deaths a tragic and poignant moment.

In terms of personal development, Kenta does not undergo a significant transformation but rather remains a consistent force of integrity and direct action. His dedication to protecting his friends, particularly Mizuki, ultimately defines his actions in the final stages of his life. He possesses no special abilities or unique knowledge that sets him apart from the other students, relying instead on his physical courage and his conviction to stand by his principles in the face of absolute terror. His character serves as a moral counterpoint to the more pragmatic and desperate survival strategies employed by others in the class.