Akira Tendō is the central character of the story, a 24-year-old man whose life is dramatically transformed by the arrival of a zombie apocalypse. Before the outbreak, Akira was an employee of a notoriously exploitative "black company" where he was subjected to crushing overwork, unpaid overtime, and a toxic environment that drained him of his former spirit. Having entered the workforce with bright dreams and a cheerful, optimistic personality, years of this treatment left him in a state of deep depression and exhaustion, to the point of expressing near-suicidal despair.

The zombie apocalypse serves as an ironic liberation for Akira. Instead of feeling fear, he experiences an overwhelming sense of freedom upon realizing he no longer has to go to work. This event effectively resets his personality, allowing him to cast off the restraints of his former life and revert to a more childlike, optimistic, and impulsive version of himself. His core motivation becomes to live life to the fullest, driven by the urgent realization that his time is now limited. This leads him to create a "bucket list" of one hundred things he wants to do before he becomes a zombie, transforming his existence from one of drudgery to a joyful pursuit of personal goals and experiences. He lives entirely in the moment, often making decisions that are inefficient or risky, but that allow him to finally experience the joys he had been denied.

In the story, Akira serves as the initiator and emotional core of the main survivor group. His initial acts after the outbreak include confessing his love to a former coworker, Saori Ohtori, and reconnecting with his best friend from his university rugby days, Kenichirō Ryūzaki, also known as Kencho. His friendship with Kencho is a key relationship, as they support each other and share in the goal of completing the bucket list. His primary love interest becomes Shizuka Mikazuki, a pragmatic and cautious risk analyst who is initially his polar opposite. While she dismisses his reckless behavior, they eventually become travel companions, and a strong romantic tension develops between them as she learns to trust his optimistic and humanistic approach to survival.

Akira undergoes significant development by confronting the trauma of his past. A pivotal moment occurs when he reunites with his former boss from the black company, a figure who represents his old life of exploitation. Initially, he is emotionally weakened and nearly falls back into a submissive mindset, but he ultimately overcomes this trauma, clearly asserting his independence and rejecting his former oppressor. This victory solidifies his new identity as a free man. His journey also takes on a new purpose when he returns to his family home and learns his father is ill, motivating him to travel across Japan in search of a doctor and a cure for the zombie virus.

Akira possesses several notable abilities that aid in his survival. A former rugby athlete, he is in peak physical condition, granting him extraordinary speed, agility, and stamina that allow him to outrun and outmaneuver hordes of zombies. He also displays feats of great strength, such as tackling massive zombies through walls and doors. In combat, he often serves as the group's main fighter, sometimes donning a specialized shark-proof suit that allows him to engage zombies in close quarters without the risk of being bitten. His greatest asset, however, is his unshakeable optimism and charisma, which not only drive his own actions but also inspire and change the people around him.