THE TWO MEN of Run the Jewels each employ a different metaphor to convey the pair's unprecedented compatibility.

El-P compares his work with Killer Mike to a mutt. "The truth about breeding and mating is the further you go from where you are, the stronger the results will be," says the Brooklyn native, revered for his forceful work in New York's underground. He compares the diversity of a mutt's lineage to the drastically different schools of rap from which he and Mike have long graduated.

Killer Mike chooses a more Southern metaphor—one representative of his Atlanta upbringing—by likening the duo's product to Brunswick stew, a thick, tomato-based dish found in Georgia, which marries meats, vegetables, corn, okra, and beans in one steaming bowl. As Mike simply puts it, "Tomato soup is tomato soup, but it ain't nothing as good as Brunswick stew."

The duo's sound grips listeners because it's regionally ambiguous, incorporating the soul of the country and grit of the city. Mike's boisterous delivery weaves intricately into El's serpentine instrumentals. Their toe-to-toe banter on tracks like "Oh My Darling Don't Cry," off October's Run the Jewels 2, presents two rap outlaws, covering one another as they rob the fuckboy bank dry. In truth, they're liberal vigilantes, carefully relaying criticisms against the government, law, and organized religion.

Their partnership was utterly unforeseen; the story goes that some Cartoon Network executive set them up on a bizarre rap blind date. Now it's serious, as Mike calls El his soulmate. In rap terms, he says, "I have what Snoop Dogg had with Dr. Dre. I don't have a producer that makes me beats, I have a producer that understands my soul."

Both El-P and Killer Mike's appreciation for one another runs deep, because the two Run the Jewels records—each released as free digital downloads—have garnered the notoriety and critical success they've each deserved for decades. Sure, Mike has a Grammy for an OutKast feature, and El-P co-founded one of the foremost indie rap labels in Definitive Jux, but with both at age 39, this is their prime.

"You're looking at two guys who have stayed on the edge of their craft and never given up on their love for music," El-P says. Like any infallible kinship, what they've created together outshines what came before.