Millie is one of the four main characters in Helluva Boss. She is the bruiser of Immediate Murder Professionals (I.M.P), a startup assassination business that carries out its services in the living world. 

Millie is very lively and cheerful. Often with a smile on her face and rarely standing still, she is a clear extrovert and isn't afraid to speak her mind. Whether it's expressing her excitement or flipping off a coworker.

Also, as Millie is the bruiser of Blitzo's employees and seems to enjoy her job, it can be assumed she's tough and very violent as well. According to Moxxie, she is aggressive in the sack as well as her job.

Sound like the show, no changes.