Heisuke Tōdō, the youngest captain of the Shinsengumi's Eighth Division, hails from Edo. Born in September 1844, he stands 163cm tall. Heisuke possesses a cheerful yet impulsive nature, often acting before thinking during challenges or combat. While occasionally naive and prone to speaking without forethought—sometimes inadvertently revealing secrets—he acts with earnest intentions and kindness. He shares close bonds of friendship with fellow captains Shinpachi Nagakura and Sanosuke Harada, demonstrating fierce loyalty in difficult times. His initial motivation for joining the Shinsengumi was protecting Kyoto's citizens, not allegiance to the shogunate, leading him to depart when their directives conflicted with his conscience. He later joined the Guardian of the Imperial Tomb but struggled with divided loyalties.

His relationship with Chizuru Yukimura, a female protagonist of similar age, becomes increasingly significant. Heisuke is among the first Shinsengumi members to accept her unreservedly. Their bond strengthens as he prioritizes her safety amidst political turmoil, ultimately motivating his return to the Shinsengumi despite ideological differences. After suffering critical injuries defending Chizuru from the Fury Amagiri, he consumes the Water of Life to survive, transforming into a Fury. This change imposes severe physical and psychological strains: lethargy in daylight, uncontrollable bloodlust, and fear of losing his humanity. He grapples with the knowledge that using his Fury abilities hastens his lifespan depletion, culminating in existential dread over his inevitable disintegration into ash. Chizuru provides stability during this period, refusing to see him as a monster and offering unwavering emotional support. Protecting her becomes Heisuke's primary purpose, helping him endure his condition.

Within the Warrior Spirit of the Blue Sky film narrative, Heisuke participates in the Shinsengumi's retreat after their defeat at Toba-Fushimi. While spying on Kodo Yukimura's castle, he rescues Chizuru from imprisonment. Later, he aids in warning allies about an impending Fury army attack. During the subsequent battle, he exhausts his Fury powers to protect Hajime Saito, sacrificing his life.

In the spin-off Hakuoki: SSL, set in a modern high school alternate universe, Heisuke is depicted as Chizuru's childhood friend and neighbor. He encourages her enrollment at Hakuo Academy, and their daily interactions gradually evolve into romantic feelings. Aware of rival suitors, Heisuke confesses his love, and Chizuru reciprocates during Valentine's Day. Their relationship is portrayed as supportive and mutually considerate, contrasting with the historical timeline's tragedies. This version of Heisuke enjoys ordinary activities like kendo and video games, free from the Fury curse.