Shibaraku Tsurugibe stands as a central narrative figure, a wandering swordsman hailing from Miyamoto Village who follows the Yagyu samurai tradition. He meets Wataru Ikusabe on Sokai Mountain's first realm, becoming his swordsmanship mentor and forging a powerful bond. His appearance features spiky brown hair, a prominent elongated mustache, thick eyebrows, and a notably large face and chin—often mocked by Himiko as hippopotamus-like. He dons a red vest patterned with black-ringed yellow circles, a navy blue ronin outfit, straw sandals, and wrist bandages, always carrying a katana and wakizashi.

Personality-wise, he embodies an invincible warrior with resolute intensity yet frequently reveals buffoonish quirks. Though his bold, brutish nature sometimes lures him into traps, he exhibits surprising perceptiveness toward subtle details. As the sole adult in Wataru’s core group, he fiercely protects and guides both Wataru and Himiko, earning their unwavering trust. His interactions oscillate between comedic failures or embarrassments and shifts into serious or romantically earnest moments, where his visual design sharpens notably.

In battle, he wields twin katanas and pilots the samurai-themed Mashin Senjinmaru, specialized for melee combat. Senjinmaru uniquely materializes only when Shibaraku enters a telephone booth—a requirement triggering recurring scrambles to find one mid-conflict. His techniques include "Flaming Rend" (1.6x damage with area-aftermath effects), "Armor Pierce" (defense reduction), and "Help, Senjinmaru!" (self-heal with temporary immunity but immobilization). His signature talent is "Secret Skill - Wild Ox."

His arc spans multiple installments: In *Mashin Hero Wataru 2*, he suffers brainwashing while shielding Wataru, critically challenging his guardian role. He reappears in the 2020 special *The Seven Spirits of Ryujinmaru*, continuing his mentorship in the post-*Wataru 2* parallel continuity. Throughout the franchise, he affectionately calls Senjinmaru "Sen-chan" and himself "Shiba-chan."