Byakko is one of the four legendary beasts—alongside Genbu, Seiryu, and Suzaku—summoned as shikigami by Kaoru Okita of the Mobile Shinsengumi. These spirits act as weapons against unlicensed monsters threatening Kyoto. Byakko manifests alongside its counterparts when Kaoru unleashes their true power, typically during critical combat situations to aid her teammates.

Visually depicted in a stylized or cute manner, Byakko embodies the white tiger among the four celestial guardians. Its presence relies entirely on Kaoru Okita’s spiritual techniques, which channel these legendary creatures. Summoning occurs under specific conditions, often when Ryunosuke Sakamoto and fellow Shinsengumi members confront grave danger.

In personality, Byakko exhibits stoicism and seriousness, carrying an air of authority. It demonstrates unwavering loyalty to the Shinsengumi’s mission, approaching combat with strategic focus and prioritizing comrades' safety. The spirit maintains a disciplined, duty-bound demeanor during operations. Its narrative function centers exclusively on combat support within Kaoru Okita’s abilities.