Bardwin is the prime minister of the Sun Kingdom, biological brother of the late king and Livius's uncle. Though he could have taken the throne, he declined and instead respected his brother's wish that Livi becomes the successor. He left the kingdom after having a falling out with Livi only to come back upon hearing news of the latter's fiancée, Nike. He was sent to prison by Livi under false pretense than he is having an affair with Nike his fiancée, later he and Livi were set up by Nike to iron out their differences where he was reinstated as the kingdom's prime minister.

It was revealed that he had a brief relationship with Livi's mother, Sheila.

(Source: Soredemo Sekai wa Utsukushii Wiki)