A girl was picked up by a shinigami in a temple inside a forest. She was then trained in all sorts of martial arts skills by the shinigami in the name of observation until one day the shinigami disappeared without notice. In the hands of a sad girl, a jet-black sword left behind by the shinigami was held.
A girl who stepped into the world with a firm determination, volunteered to the Kingdom to search for information. Over time, the girl is feared as a god of death against the background of overwhelming armed forces!