For weeks, Ukrainian troops braced for an unfamiliar enemy: North Korean soldiers sent to bolster Moscow’s forces after Ukraine launched a lightning-fast incursion and seized territory in Russia's Kursk region over the summer. Unlike the Russian troops Ukraine has been battling for nearly three years, Kyiv’s forces were uncertain about what to expect from this new adversary, drawn into the war after Moscow and Pyongyang signed an agreement pledging military assistance using “all means” if either were attacked.