Sōri, a retired kenshi who abandoned his blade for brush and canvas, maintains a protective, near-paternal bond with Rin Asano, offering financial aid and grounded counsel while rejecting her vengeful ambitions. His daughter Tatsubo, Rin’s childhood companion, resents his neglect of mundane responsibilities due to his fixation on perfecting "swordpainting"—an unconventional fusion of blade techniques and ink artistry. Behind his self-effacing artist persona lies a shadowed history as a shogunate operative, his hands stained by assassinations and betrayals that haunt his present avoidance of overt violence, even as he navigates strategic subterfuge.

Skilled in forgery, he supplies Manji with illicit travel permits, leveraging bureaucratic loopholes to aid fugitives. Though retired, his combat instincts surface when threatened, dispatching adversaries like Magatsu Taito with calculated precision. He transforms violence into art, harvesting blood from wounded allies like Manji and Hyakurin—temporary residents in his makeshift sanctuary—though clashes arise as he prioritizes creative projects over their recovery.

Aware of the Mugai-ryu’s condemned status, he brokers information between factions, dissecting cycles of vengeance with clinical detachment during philosophical clashes with Manji. His nomadic existence with Tatsubo, fleeing authorities while balancing art and residual underworld ties, reflects a life suspended between redemption and the lingering echoes of his covert past.