Silas Weir Mitchell Silas Weir Mitchell

Grimm's Monroe may regularly morph into a wolflike Blutbad, but he undergoes a slightly different transformation when the show returns.

On Friday's episode (9/8c, NBC), Portland cop Nick (David Giuntoli) calls his pal Monroe (Silas Weir Mitchell) into the field to help solve a case. "This season Monroe is becoming more involved as an active participant as opposed to being on the sidelines and being the personal Grimmopedia," Mitchell tells

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"'The Good Shepherd' is an episode that deals with bamboozling a herd of people," he says. "There's a flock, and the pastor that leads the flock is possibly embezzling funds. Nick senses that the guy might be a Blutbad, so he sends me in to check on the guy. I go in and have to join the church."

That's right. Monroe is going undercover in a play on the "wolf in sheep's clothing" idiom. But don't expect him to go totally bad; this is our favorite cello-playing, reformed Blutbad we're talking about after all.

"I'm not going in as backup in a gunfight," Mitchell says. "It's outside of Monroe's comfort zone, but the 'disguise' that I'm wearing isn't so far from the truth. I'm not going in being something completely different from what I am. If this guy is a reformed Blutbad, then I can relate to him somewhat. I feel as though I'm doing something that's good in the world. That fits in to my scheme of things, instead of running around ripping arms off of people."

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Monroe is enjoying this shift in responsibility, partly because of his unique Blutbad insghts, but also partly because Nick's detective partner Hank (Russell Hornsby) is now in on the series' big secret: Nick is a Grimm who can see the Wesen's creature-like identities underneath their human guises.

"Now that Hank has been told what's going on, there's somebody else there that Nick can talk to about that world," says Mitchell. "But Monroe knowing that Hank knows is not cool really. It's kind of like a fissure in the space-time continuum. It's beginning the journey into a whole new world. There are laws that govern how the Grimms see the Wesen, and so there are laws that govern how the laypeople may possibly see them. It's opened that world a little bit more, revealing more rules we didn't know about previously."

Wesen perspectives and crimefighting contributions aside, Monroe is a fan-favorite character for his very human (and humorous) cultural and domestic pursuits. Need a recipe for beet sausage? Want to borrow an antique picnic basket or get your watch repaired? Monroe is your Blutbad! And there might be another side to the character to celebrate in the future. "Monroe likes holidays, and there are certain holidays that he really loves," says Mitchell. "He likes to plan things, and enjoys delving into the history of holidays. I think Halloween is a very exciting time for Monroe."

Grimm airs Fridays at 9/8c on NBC.