Information about a character named Jikū from an anime titled Spirit Warrior could not be found. A search did identify a master named Jiku Acarya, also known as Jiku Ajari, from a manga and anime series that is occasionally referred to by the same English title. In that work, Jiku Acarya is the master of the protagonist Kujaku, a young monk who performs exorcisms and hunts demons. This character serves as a senior monk affiliated with the secret organization Ura-Koya, which specializes in demon hunting. No additional details regarding Jiku Acarya's background, personality, motivations, development, or notable abilities were available in the search results.