Teito Kage Monogatari
帝都影物語
Kazuya, a boy from a humble rural village, bears an uncanny resemblance to Harunomiya, the emperor's son who suffers from poor health. Summoned to the Imperial Court, he is asked to act as the prince's double, a shadow warrior in a world of opulence and danger.
Everything about Kazuya—his language, his behavior—is foreign in this glittering yet treacherous environment. As he struggles to adapt, he must protect Harunomiya, who is considered the next emperor, from the court's hidden schemes and political intrigue.