Features long blonde hair parted down the middle, a scar on his left jaw, and sharp blue eyes with prominent sclera. Stands 180cm and weighs 73kg. He wore his hair in a ponytail when he was first recruited into ORDER. He dropped out of a Kansai assassin school and lived as a delinquent before being scouted by Yotsumura, who recognized his talent. As one of the more level-headed members, Shishiba often leads the others and acts as the representative for ORDER. He has a cool, dry personality, but as a Kyoto native, he possesses a strong spirit and occasionally shows a sly side. He prefers simplicity and dislikes overthinking. While dedicated to his duty as a killer, he is fully aware that it is not a clean profession. Consequently, he believes civilians should never be dragged into the underworld and feels that killers who take lives have no right to mourn the deaths of those around them. Even if a comrade dies or he has to kill a former ally with his own hands, he maintains a cold exterior to fulfill his mission. Despite this icy demeanor, he is actually quite affectionate and considerate. He is proven to be one of the strongest even among ORDER. His weapon of choice is a claw hammer—a simple design compared to the chainsaws and multi-tools used by other members, reflecting his distaste for hassle. He prefers a combat style that inflicts heavy damage with the hammer head or slashes enemies using the claw like a blade. He is a master who demonstrates high versatility with just a hammer, such as breaking an enemy's neck by finding a blind spot or parrying bullets. Hailing from Kyoto, he speaks in Kansai-ben. He has an extreme hatred for onions; unlike his usual sensible self, he loses his temper and goes on a rampage if onions are found in his food. It is estimated he has been working for the Assassin Association for at least 8 years.