The story flows to Kenshin Himura, who was before popular for being a "Battousai - the Manslayer."
Nevertheless, owed to an unpleasant happening, he put off the sword that destroys and decided he would never kill other human beings, no matter what. He seized up a reverse-blade sword. This way, even though he used the effective Hiten Mitsurugi style and could still defend others without killing.