The NBC fantasy drama - which follows homicide detective Nick Burkhardt (David Giuntoli) as he wards off supernatural beings - was picked up for another run last month.
Mitchell, who plays the wolf-like Monroe, told Collider that he is keen for his character to keep his "dangerous side".
"I would like to see Monroe put into a position where he has to use his strength and he's cornered," he suggested. "I don't want him to lose the dangerous side of himself.
"Other than that, I feel like the writers are giving me really fun stuff to do and I love where the stories are going."
Mitchell also praised fellow cast member Bree Turner, who plays Rosalie.
"She's great to work with [and] we have a good time," he said. "So, I like where it's going. I just want to make sure that we don't lose touch with [Monroe's] violent inner nature."
Forthcoming guest stars on Grimm include David Zayas (Dexter), Roger Bart (Revenge)and Kenneth Mitchell (Jericho).
Grimm airs on Fridays at 9pm on NBC in the US. In the UK. the show airs on Mondays at 9pm on Watch.
> The 2012-13 season TV scorecard: What's axed? What's renewed?
Watch a promo for Grimm below: