Miyamoto Iori is a historical samurai figure in the Fate series, serving as the stepbrother of Kaya Ogasawara and adopted son of The Book of Red Jade. He rose through ranks to become a clan lord at 20, domain samurai captain and swordsmanship instructor at 25, and chief minister at 26 after contributing to the Shimabara Rebellion. Known for his exceptional organizational and analytical abilities, Iori maintains a philosophy centered on understanding opponents to achieve victory. He practices restraint in killing, preferring to subdue enemies non-lethally unless involved in formal ceremonies. Despite his outwardly upright demeanor and good relationships with those around him, Iori harbors a ruthless nature beneath the surface, kept in check only by his connection to Kaya. His flexible mindset allows him to quickly accept unconventional situations, such as encountering a female version of his teacher from another world.