Captain Sean Renard is a police captain who is Nick's politically adept superior officer, a member of the creature community of unknown origin, and a Zauberbiest (male form of Hexenbiest). Nick is totally unaware of his status and he seems to be a potential threat. He is addressed as Your Highness, further implying that he belongs to royalty in the creature community. He also references my canton, implying a leadership role, which is further shown when he appears to police and protect wesen engaging in illicit acts.

He seems to want a return to the old ways. He consumed a potion that would make him pure of heart so that he could wake Juliette, wanting to keep her active so that he could ensure Nick's continued presence in his city. His brother, Eric, mentioned to Adalind that Sean Renard's mother was a Hexenbiest and that he is only half of a royal (hence one reason why Catherine Schade referred to him as a bastard). Because his mother is a Hexenbiest but his father isn't Sean is a half-Hexenbiest. It is implied that Sean would have inherited Eric's position had he been legitimate.

He has begun to develop a complicated attraction to Juliette due to his role in awakening her from the coma, but is attempting to resist it due to his artificial nature and because he is, in his own way, an honorable man. The most likely explanation is that separating Juliette from Nick interferes with his plans for Nick. In fact he stated outright that he wanted to awaken Juliette because it served his purposes. He, Nick and Juliette all drink a potion mixed by Rosalee that is supposed to break the connection that was formed when he woke Juliette from the coma. Since the revelation of his heritage Sean has been more open with Nick about Grimm-related cases, also admitting his own distance from his family and preference for Nick over them, although Nick still prefers to work with Hank, Monroe and Rosalee.