As head of the Pubyok, Division 42's old-school, hardcore torture squad, Sarge's job is to break heads and ask questions later. In some ways, he's the polar opposite of the intellectual Interrogator, who feels that interrogation work is an art form.
While Sarge is a throwback to an even scarier historical moment in the Kim regime (as is Officer So), he is in some ways a more genuine character than the Interrogator. At the very least, he wears his heart on his sleeve, openly attacking subjects who sass him or offend his sense of North Korea's honor.
Sarge is judgmental and hotheaded, and he has no use for "psychology." He's a classic chauvinist and hates the idea of a woman in the hallowed halls of Division 42—until Q-Kee learns how to act like one of the guys, that is.
In the end, Sarge triumphs. And with his triumph, North Korea is pulled even further back into the darkness of suffering and brutality that marked that beginning of the Dear Leader's regime.