B Cell is a youthful male lymphocyte with brown hair and gray eyes, clad in a standard uniform and armed with an antibody gun engineered to secrete targeted antibodies against specific antigens. Confident in his skills, he craves recognition and bristles at being overlooked or disrespected. Functionally, he excels at producing antibodies to combat pathogens like bacteria and viruses, relying on Memory Cell’s antigen-specific intel for precision. Their collaboration enables accurate immune responses, though antibody preparation delays pose a tactical constraint.

In the pilot chapter *The Story of Cells*, B Cell resists cooperating with fellow immune cells during a cancer cell crisis, reflecting his role in a discordant team dynamic that contrasts with later adaptations. This version introduces a cell reincarnation system—where expired cells regenerate—though the concept fades in the main series.

His antibody gun evolves through upgrades, becoming lightweight and efficient, later described as “feeling like air.” Its Y-shaped design mirrors real antibody structures, optimizing antigen neutralization. While primarily focused on antibody production, B Cell adapts to high-stakes scenarios through temporary alliances with Killer T Cell and Natural Killer Cell, balancing teamwork with his preference for solo operations.

Consistently portrayed as a B lymphocyte within the immune hierarchy, he drives adaptive immunity via antibody generation. His partnership with Memory Cell underscores immunological memory, enabling rapid responses to recurring threats. Spin-offs and main series alike maintain his core traits, with no significant shifts in personality or role across adaptations.