Sarutobi Sasuke operates as a ninja of the Takeda clan, functioning as Sanada Yukimura's personal informant and retainer. His duties focus on intelligence gathering, reconnaissance, and protecting Yukimura during wartime. Sasuke exhibits extraordinary agility and speed, enabling him to match a galloping horse's pace and move unseen. In combat, he wields two large shuriken connected by a razor-thin, near-invisible wire, manipulating their flight path with precision. He also summons a crow familiar for aerial maneuvers or gliding.

Personality-wise, Sasuke maintains a laid-back, often cynical demeanor, frequently appearing lazy or disinterested. Despite this outward attitude, he shows steadfast loyalty and a powerful sense of duty, reliably accomplishing missions. His bond with Yukimura transcends formal service, marked by mutual respect and near-familial concern, where Sasuke often acts as both protector and advisor. He shares a competitive relationship with Kasuga, a kunoichi from the rival Uesugi clan, habitually teasing her about marriage to elicit reactions; their rivalry primarily centers on contests of speed and ninja prowess.

During the conflict against Ishida Mitsunari and the resurgence of Oda Nobunaga shown in *Sengoku Basara: The Last Party*, Sasuke fights alongside Yukimura, Date Masamune, and others at the Battle of Sekigahara. He participates in the final clash against the resurrected Nobunaga, contributing his skills to the united effort that defeats the threat. Throughout these events, Sasuke remains consistent as a support tactician and combatant, utilizing stealth and mobility without shifting allegiance. His background as a Kōga ninja and legendary folklore origins—including tales of being orphaned and raised by monkeys, explaining his moniker "Sarutobi" (meaning "monkey jump") and tree-dwelling agility—inform his depicted capabilities.