Soto Takahiro was born as the cambion grandson of Anamurumon, a would-be Minkaian usurper-turned-wind yai oni. Anamurumon trained the boy from birth to usurp the Jade Throne in his place (which he could no longer achieve after his transformation into an oni), starting with secretly poisoning his mother in childbirth so Takahiro would have no other family member to bond with other than himself.2
At a young age, Takahiro joined a samurai order devoted to the protection of the Higashiyama clan, and became the bodyguard of Shigure, the youngest child of the then-emperor. Shigure grew close to Takahiro and considered him more of a brother than his actual siblings. Takahiro would intentionally throw their sparring matches, while Shigure in turn completed Takahiro's history and culture homework, both duping their instructors that they had mastered their lessons.23
When the oracle Renshii Meida, the descendant of a clan that once served Anamurumon during his human life, offered her services to the Higashiyama family, she was seduced by Takahiro and became his lover. During this time, Anamurumon secretly arranged the deaths of Shigure's older siblings, leaving Shigure as the heir. When Shigure rose to the throne, he named Takahiro his bodyguard and Meida his advisor.2
A week into the new emperor's reign, Takahiro and Meida convinced him that there would soon be an attempt on his life. He agreed to hide in the Imperial Shrine, a magical island on which only those with imperial blood and their chosen guardians could set foot. Takahiro further convinced Shigure to grant him the Higashiyama Seal and name him the regent of Minkai so he could lead the country in Shigure's absence, but as soon as that was done, Takahiro killed Shigure and threw his corpse into the Well of Demons. Returning to the mainland, Takahiro proclaimed himself the Jade Regent and selected Anamurumon as his advisor, who had his oni minions spread stories that the emperor had gone into hiding while the threat to his life remained.2
Due to the lack of divine mandate that Shizuru originally granted to the five Minkaian imperial families, the Jade Throne does not accept Takahiro as emperor as long as the last legitimate heir is still alive. His short reign has ushered in an age of unrivalled excess, debauchery, and unrest.14
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