Minamoto no Raikou is the older brother of Minamoto no Hikaru and the heir of the Minamoto clan. He is renowned in the capital as a skilled archer and a legendary warrior. In the story, he is entrusted by the Emperor with the mission to recover the lost magatama jewels to save the capital from corruption and disease. However, he falls victim to the same epidemic that plagues the city and becomes too ill to travel. His younger sister Hikaru secretly takes his place, disguising herself as Raikou to undertake the quest. Raikou thus serves as a catalyst for the journey, his absence forcing Hikaru to step into his role. His personality is that of a dedicated and disciplined samurai, resolute in his duty and commanding respect. He is assertive and independent, yet his illness renders him helpless, highlighting the vulnerability even of the strong. His key relationship is with his sister Hikaru, whom he trusts enough to allow her to take his place, though he remains unaware of her actions for much of the story. He also has retainers who accompany Hikaru. Minamoto no Raikou's primary ability is his exceptional archery, which is widely acknowledged. His character development is limited due to his early incapacitation, but his legacy and the burden of expectation drive the plot forward.