Reishin Kou, former Minister of Civil Administration and ex-head of the Kou clan, balances political acumen with intricate familial loyalties. As Li Kouyuu’s adoptive father, he rescued the boy in childhood yet cultivated a distant facade, masking covert efforts to advance Kouyuu’s career through education and political advocacy. This duality extends to his siblings: younger brother to Kou Shouka and Kou Kurou, Reishin inherited clan leadership after Shouka’s departure, discreetly delegating Kurou as proxy head while shielding Shouka’s secret identity as the assassin Black Wolf.

His marriage to Princess Yuri, half-sister of Emperor Senka, stemmed from childhood affection for her disguised persona, Yuzuriha—a bond he initially rejected until Shouka declined the arranged match. Reishin’s protectiveness manifests most fiercely toward niece Kou Shuurei, whose lineage he concealed for years, fearing her resentment over supplanting her father. He covertly engineered her Imperial Exam participation, triggering corruption accusations, house arrest, and a clan-led government shutdown until his exoneration.

Outwardly jovial and mischievous, Reishin earns allies’ wariness for his calculating ruthlessness. He forges masks for friend Ko Kijin, disregarding societal unease, and shares a strategic rapport with official Tei Yuushun. A master of the biwa, he channels the Kou clan’s artistic heritage.

His downfall unfolds as Shuurei uncovers their kinship, resulting in his ousting from the Ministry and retreat to Kou province. Stripped of political power, he navigates strained ties with Emperor Ryuuki, whose marriage to Shuurei intertwines their familial histories through Yuri. Reishin’s legacy lies in clandestine sacrifices for family—a tapestry of concealed bonds, manipulated destinies, and quiet withdrawal, underscoring the weight of duty against personal ambition.