Sôichirô Amano, born into financial hardship in 1965, graduated from the private Meguro River Academy. Through determined effort, he became the wealthy owner of a prominent hotel chain, accumulating multiple properties and vacation homes. His resources allow him to effortlessly provide assets like a large family mansion. He possesses dark brown hair and black eyes, bearing a noticeable resemblance to his biological son, Nagi Umino. His personality presents as affable and understanding on the surface, but underlying traits include being calculating, conniving, and exceptionally difficult to read. He consistently maintains a calm, relaxed demeanor while deliberately concealing his true thoughts and intentions. This evasiveness makes him unpredictable and contributes to interpersonal distance. His adoptive daughter Erika Amano finds him uncomfortable to interact with, describing him as someone who "never lets his guard down." He employs diversionary tactics in conversations, exemplified when avoiding direct answers to Nagi's questions about Sousuke Amano. His familial relationships are complex and often strained. He is the biological father of Nagi Umino and Sachi Umino, and the adoptive father of Erika Amano and Sousuke Amano. Despite stating a desire for Nagi and Erika to develop a relationship, Nagi feels no closeness to him, partly due to Sôichirô's enigmatic behavior and cryptic remarks. Erika experiences persistent discomfort in his presence, resulting in a tense dynamic. His relationship with his biological older son, Sousuke, is marked by conflict; Sousuke disappeared prior to the arranged marriage between Nagi and Erika and later resurfaced with the stated motive of "destroying the Amano Clan" while working for a rival hotel company. Sôichirô initiated the arrangement compelling Nagi and Erika to cohabit in one of his mansions following discussions with both families about their engagement. This decision stemmed from the discovery that Nagi and Erika were switched at birth. He framed the cohabitation as an opportunity for them to potentially develop romantic feelings before graduation, claiming he would respect their wishes if no relationship blossomed. He periodically observes their interactions but typically avoids overt interference. His actions frequently involve ambiguous statements, such as suggesting to Nagi that "even if you marry your little sister Sachi, things will turn out fine," which confuse rather than clarify situations. He contrasts significantly with Nagi's adoptive father, Yôhei Umino; where Yôhei is straightforward, Sôichirô operates through indirectness and obfuscation. While not malicious, his methods and communication style often create emotional distance.