There have been plenty of fantastic special guest actors in Starring David Giuntoli as Nick Burkhardt, a homicide detective in Portland, Oregon, who's descended from a line of monster hunters and sworn to protect humanity from all sorts of evil creatures.

Grimm features a monster-of-the-week style of storytelling, which means there have been quite a few guest stars in Grimm over the years. Because the monsters often disguise themselves as humans, these characters were often played by notable guest actors. The best of these guest actors in Grimm weren't great because you could point at them and say where you recognized them from. They were the best because they brought their skills and unique styles to the show, elevating those around them. It takes a special actor to be a good guest star, and these are the best Grimm has to offer.

5 Cary-Hiroyuki Tagawa

Takeshi Himura

Takeshi Himura is an Inugami Wesen, played by Japanese-American actor Cary-Hiroyuki Tagawa. Takeshi appears in one episode of Grimm season 5. In the episode, titled "Inugami", Takeshi is a lawyer working for the Akagi family, seeking justice for the Akagi's son's death. The Inugami code forces Takeshi to protect the Akagis in any way he can, so when he doesn't get justice in the courts, he seeks it extrajudicially.

Nick attempts to stop Takeshi from seeking his revenge for the Akagi family, but, in the end, is forced to kill him. Himura has frequently been cast as a villain in his career, playing Chang in The Last Emperor and Tokugawa Tsunayoshi in 47 Ronin. He can play menacing easily, and his portrayal of the deadly but honorable Takeshi is an interesting look into a different kind of Wesen. There's honor in the violence he doles out, but it's violence nonetheless.

4 C. Thomas Howell

Agent Weston Steward

C. Thomas Howell appears in Grimm as Agent Weston Steward, an FBI agent and a Wesen in four episodes of season 3. Weston was a vengeful and corrupt official who was secretly working for the Verrat, specifically for Prince Viktor (Alexis Denisof), who tasked Weston with finding and killing Sean (Sasha Roiz) and Adalind (Claire Coffee). However, Nick and his team got to Weston first and interrogated him, finally leaving him with a fake address for the prince.

Humiliated, Weston returns for revenge, only to have his head unceremoniously sliced off. Howell is best known for his roles in the 1980s, like Red Dawn, The Outsiders, and Secret irers​​​​​. Howell brings a quiet aspect to his performance, but you can tell there's something raging under the surface, and it's satisfying watching Weston's calm demeanor shattered by Nick.

3 Arnold Vosloo

Jonathon Wilde

Arnold Vosloo appears in season 4, episode 12, "Maréchaussée", as Jonathon Wilde, a Wesen manticore bounty hunter. Wilde is a powerful and dangerous Wesen who takes on contracts from the Wesen Council, as well as anyone else willing to pay him. With his stinger tail, he easily dispatches a handful of targets in his one episode on the show. While Nick and his team are on his trail, Wilde is following them as well. The Wesen Council ordered the hit on Nick, much to Wilde's surprise.

Wilde nearly gets the drop on Nick before he's killed by Juliette Silverton (Bitsie Tulloch). Vosloo is best known for his role in the Mummy series as the titular Imhotep, but he also memorably played Colonel Coetzee in Blood Diamond and Habib Marwan in 24. Vosloo brings his menacing, but charming presence to Grimm, and if he weren't killing everyone, it would be hard not to root for Wilde.

2 Titus Welliver

Farley Kolt

Titus Welliver plays Farley Kolt in Grimm season one for one episode. Kolt is a Wesen who is searching for a collection of ancient and valuable coins, a search that brings him into with Nick, who is suspicious of the Wesen, especially when it's revealed he was present during a double murder. It turns out that Kolt had actually dated Nick's aunt for a time and fondly re their romance. Nick comes to believe Kolt, and Kolt realizes Nick was the nephew that Marie Kessler (Kate Burton) left Kolt to take care of.

Both men bond over their love of Marie, and Nick comes to trust Kolt. While Kolt is not responsible for the murders, he still attempts to steal the coins, though Nick thwarts him, telling him to try harder. Welliver is best known for starring as the titular character in Bosch, Silas Adams in Deadwood, and the Man in Black in Lost. He plays a similar character in many of his roles, including Grimm. Kolt is a street-smart Wesen who acts rough on the outside but has a much warmer interior.

1 Dee Wallace

Alice

Dee Wallace plays the Wesen Alice in three episodes of Grimm season 3, though she's mentioned in nearly every season of the show. Alice is Monroe's (Silas Weir Mitchell) mother and comes to visit Portland with her husband, Bart (Chris Mulkey), when Monroe announces he plans to wed Rosalee (Bree Turner). Alice and her husband have an old-fashioned view of the world and don't think Wesen should marry Wesen of another species.

It's a classic, Meet the Parents style of episodes in Grimm, just with the added flavor of monsters

Though Alice is not as vocal about her disappointment as Bart, she makes her disapproval clear. However, Alice and Bart eventually warm up to the idea and even end up buying a new wedding dress for Rosalee. It's a classic, Meet the Parents style of episodes in Grimm, just with the added flavor of monsters. Wallace is the perfect guest actor for the part, playing the doting mother who only wants the best, but also has a ferocity that you would not want to be on the wrong side of.