Hiruma Kihei (比留間 喜兵衛) is the elder brother of Hiruma Gohei and, effectively, the brains behind their dastardly duo. Hatching a plot to take the land upon which the Kamiya dojo stands in order to sell it, Kihei hatches a plan to worm into Kamiya Kaoru's trust and stays at the dojo as a sort of live-in apprentice immediately after the death of her father, Kamiya Koshijiro. When his attempts to persuade her to sell the dojo fail in the face of her pride and stubbornness, Kihei enlists the help of his brother to discredit the dojo by posing as the Hitokiri Battōsai and claiming to be a former student of Koshijiro's. However, when the real Battōsai appears, the two brothers are swiftly defeated and cast out.
Kihei and Gohei return shortly afterward, having hired the "Fight Merchant" Zanza to defeat Battōsai for them, but when Kihei hatches a plot to betray Zanza, the Hiruma brothers are once again defeated. They return once again during the Jinchu arc as the bodyguards of the yakuza boss Fudōsawa, but are unfortunately met and trounced a third time by Zanza.