Kushimaru took pleasure in the very process of killing and often let out a maniacal laugh while finishing off his victims. He was extremely cruel and cold-blooded, feeling no remorse whatsoever. Among his atrocities was even the murder of his own mentor. Together with Jinpachi Munashi, they formed a duo nicknamed the "Heartless Pair" for their ruthlessness. He often bickered with Jinpachi, but in battle they acted in unison. Kushimaru fiercely protected the honor of the Seven and could not stand when someone outside its ranks dared to wield one of the legendary blades. Stealth was his second nature; he masterfully employed Silent Killing in the mist. He showed not a drop of mercy to his enemies, crucifying them for his own amusement. His personality combined sadism, pride, and absolute unscrupulousness. Even among the cruel swordsmen of the Mist, he stood out for his mercilessness. He did not seek compromises and resolved disputes solely by force.