Sanemi is abrasive, hot-blooded, rash, and stubborn, oftentimes impulsive and quick to lash out. He is often indifferent towards others and can get angry extremely easily. He has a younger brother named Genya, though he always denies his relationship with Genya. Sanemi has also displayed a hunger for battle and will often pick up fights with random people. When Genya joins the Demon Slayers in search of him, Sanemi repeatedly dismisses and lashes out during any chance of seeing him.