From Grimm wiki
Monroe
Monroe is a Blutbad who becomes a loyal friend and essential ally to the Grimm detective Nick Burkhardt in Portland.
Monroe is a reformed Blutbad who initially encounters Nick Burkhardt as a reluctant informant after Nick discovers his heritage as a Grimm. Despite the historical animosity between Grimms and Wesen, Monroe chooses to break from his predatory nature, eventually becoming Nick's primary consultant on supernatural matters and a bridge between the human and Wesen worlds.
Role and Relationships
Monroe provides critical knowledge regarding Wesen culture, history, and lore, which proves vital to the investigations conducted by Nick and his partner Hank Griffin. He later marries Rosalee Calvert, a Fuchsbau who operates the spice shop that serves as a frequent meeting point for the group. His close-knit circle of allies also includes Captain Sean Renard, Sgt. Wu, and Juliette Silverton, all of whom rely on his unique perspective to navigate the dangers of the Wesen community.
Character Traits
Unlike many of his kind, Monroe is a clockmaker and a lover of classical music and fitness, often struggling to suppress his natural instincts. His commitment to Nick's cause often places him in significant personal danger, yet he remains a steadfast protector of his friends and a key figure in maintaining the precarious balance within Portland's hidden supernatural society.