A Taimanin and one of the leaders of the prestigious Koukawa family. Probably born around the year 2044. She is the oldest daughter of one of the sidearm of the Koukawa clan, which protect the main branch of the family. Oboro was put in charge as the guardian of the future clan head Koukawa Asuka. She is a user of a Ninja Art, which is considered especially powerful, which allows her to move her own soul into another target. She was the only known sibling which awoke to a Ninja Art, unlike her brother Koukawa Rei now known as Ares, and unnamed sister now known as Li Mayfeng. Her brother Rei, would leave after losing most of his body during a mission in which he saved the life of the mistress of the clan patriarch, and missunderstood Oboro's concern if he should continue to be a Taimanin, as a sign to be thrown away as a useless monster.