Akita Tōshirō is a tantō sword forged by the swordsmith Awataguchi Yoshimitsu, placing him among the group of swords known as the Tōshirō brothers. His long history as a treasured blade has shaped his curious and observant nature, as he shows great interest in anything related to the outside world.

In terms of personality, Akita is gentle and somewhat reserved, but his defining trait is his fascination with secrets. He enjoys collecting secrets and has a special skill for hide-and-seek, which he uses to uncover new information. This quiet hobby sometimes leads to him being overlooked or forgotten by his more boisterous brothers, adding a slightly melancholic layer to his character. His primary motivation appears to be a quiet desire for knowledge about the world around him, driven by the many years he spent in careful preservation.

Within the story of the citadel, Akita fulfills the role of a gentle, inquisitive presence among the large cast of swords. His ability to move quietly and his expertise in hide-and-seek are notable abilities that serve his secret-collecting hobby. His key relationships are primarily with the other Tōshirō brothers, though his quiet nature means he often operates on the periphery of their activities. Specific character development arcs are not prominently documented, but his established traits present him as a consistently thoughtful and slightly lonely figure who finds joy in small discoveries and the mysteries of daily life at the citadel.