He Needs Unguent
Gaear Grimsrud's a difficult character to understand, in part because he says so little… and in part because he's such a stone-cold sociopath.
Unlike his partner and foil, Carl, Gaear's almost mute, rarely speaking in full sentences. He's got eighteen lines in the whole film. We know he's a antifreeze-blooded murderer—he kills four people without seeming to give it a second thought. But right after the fourth murder, and with the victim's body a few feet away, he almost drops his TV dinner when a soap opera character announces that she's pregnant. What's going on in his head?
The Coens milk a lot of dark comedy from Gaear's weird personality. For example, when he and Carl are in the process of kidnapping Jean Lundegaard, she bites Gaear on the hand. Gaear screams the last thing we might expect him to scream: "I need unguent!" He feverishly rifles through the Lundegaard's medicine cabinet, until Jean jumps out of the shower behind him. There's also that way-too-insistent interest in pancakes—he's like some sick version of Cookie Monster.
Something Is Seriously Missing
Another facet of Gaear's personality is how casually he commits murder. He thinks nothing of shooting a state trooper in the head or murdering two innocent people who happen to drive by. He kills Jean simply for being "too noisy," and murders Carl with an ax for complaining about the Ciera deal.
He calmly feeds Carl's dismembered body through a wood chipper, hitting his sock-covered foot with a block of wood to make it go in quicker. He's a man who knows how to get things done. Yet despite all this horror, there's something oddly child-like about Gaear. We get the sense that he might be too dull or too damaged to really comprehend anything he's doing.
In a way, the kind of evil Gaear represents is the total opposite of that represented by Anton Chigurh in the Coen brothers' No Country for Old Men. Chigurh's almost like some metaphysically evil being, seemingly invincible, in total control, very intelligent. He's efficiently doing a job he's hired to do, and likes to have philosophical discussions with his potential victims.
Gaear, by contrast, is primitive; he does evil things because he's ignorant and limited. His bad deeds emerge from a defect inside him, in his makeup, and aren't part of some crafty, super-villainous design. But that vacant stare is definitely terrifying. You gotta wonder what it was that Shep Proudfoot was vouching for when he vouched for Gaear.
For a play-by-play of Gaear's actions, check out Carl's timeline.