I'll tell you what's going on with NK,, Kim is a paranoid little bastard, he's always worried about war with SK or the US.
North korea just signed this mutual assistance treaty with russia, they are begging putin to take NK troops because he #1 wants to show how reliable he is, #2 wants experience for his men in modern warfare, and #3 and most importantly wants to set the stage for reciprical help if they ever get into a war with south korea.,
Russia doesn't need them but will take them since it obviously makes things easier.