Ōishi Chikara (大石良金, Ōishi Chikara) is a jōnin of the Hidden Blood Tree Village and right hand of the Fifteenth Chikage. As an orphan raised by a high-born family with the goal of being the most intelligent and respected warrior in the village, Ōishi worked nearly all of her life to earn respect while keeping up with her studies and honoring the bloody history of her country. The upcoming chikage successor approached Ōishi and offered her time to train with him to build their relationship. Both were close regarding their dynamic and their relationship between them led to a friendship. Despite the young lad becoming chikage, their friendship and partnership lasted, and she became the right-man to guard and defend him until she could no longer.