Warriors From the North.(North Korea's Special Operations Force)

When Japanese investigators raised a North Korean spy ship from the ocean's depths last September, they found more than they'd bargained for. The vessel, which sank after a fire fight with the Japanese Coast Guard in December 2001, had an arsenal worthy of Arnold Schwarzenegger: rocket launchers, an 82mm bazooka, an antiaircraft machine gun and two surface-to-air missiles. But the carnage within the ship's hull revealed a second battle: when all was lost, North Korean commandos onboard executed the few surviving sailors and scuttled the ship to avoid capture. One of them, perhaps in his last act, scribbled a short message on a wooden board that was later found by the Coast Guard. It read: "To the Party, this child shall be your loyal subject forever."

Such are the ways of North Korea's Special Operations Force, an army with the killing skills of Navy SEALs but large enough to populate a small city. U.S. military estimates put the SOF's ranks at more than 100,000, making it the world's largest commando force by far. Most soldiers couldn't handle even one of these warriors in a foxhole. Well- schooled in the martial arts, they can take on several opponents at once with their bare hands. With a sniper's rifle in those hands, they are said to be able take down more than a few moving targets--at 200 meters--in 15 seconds. One of the corps's many "bravery exercises" involves sneaking across the demilitarized zone to grab a sign or other souvenir from the South. And if they fail in completing any missions, they are trained to kill themselves on the spot. Known for their unflinching loyalty to North Korean leader Kim Jong Il, their role in any future North-South conflict is to create "simultaneous war everywhere in South Korea," says a former member who defected in the 1960s.

A large part of the reason Washington is keen to resolve the Korean nuclear crisis diplomatically is because of the ferocious potential of ...