David Giuntoli David Giuntoli

Titus Welliver, best known as Lost's Man in Black, drops by Grimm on Friday, but will he bring good or evil tidings?

Nick (David Giuntoli) has unwittingly been dealing with an unknown antagonist, his very own Capt. Renard (Sasha Roiz), whose agenda is still unknown to viewers. He's apparently some sort of royalty among the creature kind and has enough pull to get others killed without getting his own hands (paws?) dirty. In Friday's episode ((9/8c, NBC ), the captain will start to exhibit odd behavior when he comes in contact with some rare coins that have turned up from a failed robbery.

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What's the story behind these coins? That's where Welliver, who plays an old buddy of Aunt Marie's, comes in. Check out the exclusive clip below to see just what his character knows. Hint: The coins have some relation to Nick's family.

Grimm airs Fridays at 9/8c on NBC.

What power do you think the coins possess? Is Capt. Renard a potential ally or a problem for Nick?