Koji Ward is a supporting character in the story, known as the father of the Ward family trio. He has a distinctive appearance, wearing rounded glasses and sporting a long white beard, and is typically dressed in a blue coat, a white shirt, gloves, and brown pants. His personality is loud and assertive, and he consistently carries a smug, enthusiastic expression. He is a cat lover, like many other survivors in the post-apocalyptic world.

His primary motivation is to protect his sons, Len and Masaki, and to secure essential supplies for their survival. He is willing to take great risks for the sake of his family. In the story, he and his sons venture into a shopping mall to gather supplies, where they become trapped by cats. Koji demonstrates notable quick reflexes, dodging an extremely agile cat and taunting it to distract it from his sons. However, he ultimately becomes infected by the virus after buying time for his sons to escape, transforming into a cat himself. His role in the narrative is that of a brave but tragic figure whose sacrifice underscores the constant threat posed by the virus. His key relationships are with his sons, with whom he operates as a close-knit family unit, and he briefly encounters the main group led by Kunagi during the mall incident. His development is limited to his sacrificial act in the episode, highlighting his protective instincts and the high stakes of the feline apocalypse.