After the Korean War, the Democratic People's Republic of Korea--aka North Korea--decided to try and follow in the path of the Nazis and the Thule Society, and weaponize magic--after all, they felt that every weapon should be on the table for when hostilities inevitably resumed, and that included magic.
And so the North Koreans began rounding up North Korea's supernatural community, placing them in to camps where they could be 'trained' to fight on behalf of the people's revolution. The Veil Treaty of course objected to this--they'd been trying to keep regimes from doing this very thing for millenia, but the North Koreans responded by dissolving all the Veil Councils in North Korea and declaring all who swore allegiance to the Veil to be enemies of the state. Hundreds of agents were killed, and the Veil Councils in Pyongyang, Hamhung, and Kaesung were destroyed--their relics 'repatriated' for the regime.
The Veil Treaty had already been put on the edge by the Thule and the subsequent formation of groups such as the British MI18 and the American Magestic-12, so they weren't about to let North Korea get away with an attack on the supernatural community of this magnitude. Working alongside the United Nations, the Veil Treaty performed one of the largest rescue operations in history, and managed to abscond with almost all of North Korea's supernatural population, as well as a number of the state's magical artifacts. In effect, the Hermit Kingdom was emptied of magic.
North Korea never forgot this insult. They felt as through they had been denied their birthright by the actions of foreign spies and wizards. And so they declared war on the Veil, and have spent a considerable amount of time and resources to 'return the Korean People's magical heritage to their rightful owners.' Of course, since most of what the North Koreans consider to be 'magical heritage' involves sapient, supernatural creatures who prefer life in Seoul or San Francisco to cages in some laboratory in Pyongyang, they don't exactly come willingly. But the North Koreans are willing to pay handsomely for any supernatural they can get their hands on--even if they aren't Korean in the first place.
Indeed, in the occult labs of Bureau 14 are filled with supernatural beings from around the world--Japanese kitsune, Iraqi jinn, Greek slyphs, Scottish bogies, Ghanan Adze, and American werewolves. They see it as recompense from the supernatural community to North Korea--fair repayment for all of the 'unjustly abducted' North Korean supernaturals. And in those labs, horrible experiments are performed on these supernaturals, discovering their weaknesses, exploring the limits of their powers, and attempting to bestow these abilities onto the loyal soldiers of the DPRK.
Sure, the North Korean nuclear program might have the potential to devastate entire cities. But their occult warfare program has the potential to be far, far worse. Nobody knows its full extent, nor do we have any idea of its successes. But considering what the Thule were able to do in a short time, the thought of the North Korean occult program sends shivers down the spines of governments and conspiracies around the world.