Bat is a significant supporting character who first appears as a young thief at the beginning of the journey. As a child, he is approximately fifteen years old and initially presents as a brash, selfish, and opportunistic survivor of a post-apocalyptic wasteland. His background reveals a more noble core; he was an orphan adopted by a kind woman named Toyo. To lessen her burden and allow her to better care for the younger orphans, Bat chose to leave his home village to fend for himself. While wandering, he was captured and imprisoned in the same village as Rin, where he encountered the Hokuto Shinken successor, Kenshiro.

Impressed by Kenshiro's overwhelming strength during his escape, Bat appoints himself as Kenshiro's sidekick and manager, hoping to use the martial artist's power as a tool for his own survival and benefit. At this stage, his personality is marked by cowardice, carelessness, and a tendency to jump to wrong conclusions. He often tries to steal from defeated enemies or demand payment for Kenshiro's heroics, acting as a bratty and insensitive kid hardened by the violent era. However, this masks a virtuous and kind nature that becomes more evident as the story progresses. The death of his adoptive mother, Toyo, serves as a pivotal moment that forces Bat to mature, and through witnessing Kenshiro's hardships and battles, he slowly grows into a more respectable and selfless individual.

As Bat travels with Kenshiro, he develops a strong brotherly bond with him. He looks up to Kenshiro as an older brother figure, and in turn, Kenshiro comes to see Bat as a younger brother. He also forms a close relationship with Rin, initially watching over her like a protective older brother, though these feelings later evolve into romantic love. Bat proves to be practically useful on their journey, demonstrating a natural talent for fixing machines and driving vehicles, most notably a dune buggy that serves as their transportation.

Following a significant time skip after the defeat of the major antagonist Raoh, Bat has grown into a young man of average height with a more muscular build and a mature appearance, often wearing his signature goggles around his neck. He has become wiser and more capable, serving as the co-leader of a resistance group called the Hokuto Army alongside Rin. This group fights against the tyrannical reign of the Celestial Emperor and its general, Jakō. In this role, Bat is a courageous and charismatic leader who protects others without hesitation.

Although Bat is not a true master of any martial art, he has developed rudimentary combat skills and a limited knowledge of Hokuto Shinken simply from observing Kenshiro's fights for so long. This has allowed him to learn how to perform a few pressure point techniques, most notably one that can induce amnesia or erase a person's memories. As an adult, he is capable of fighting on par with other skilled warriors and uses his cunning and trickery to protect his friends. His mechanical knowledge remains a key asset.

In the final arc of the story, Bat's love for Rin becomes a central focus. He is painfully aware that Rin's feelings for him are not genuine, as her memory was manipulated by a pressure point that caused her to love the first person she saw. In an act of profound selflessness, Bat uses his limited Hokuto Shinken knowledge to erase Rin's memory again, forgoing his own happiness so she can be with Kenshiro. He later poses as Kenshiro to fight a blind enemy named Bolge, who seeks revenge against the true successor. Bat is captured, tortured, and mutilated but endures the suffering, hoping that if Bolge believes he has killed Kenshiro, his friend will be safe. He is mortally wounded in the ensuing fight, but in a final act of mercy and skill, Kenshiro saves Bat's life by manipulating his pressure points, reviving him.