My point here is that the North Koreans are Koreans nationalists at heart (John McCreary has made this point a number of times in the past), as well as remaining very suspicious of non-Koreans, including the Chinese, and especially the Japanese. The recent establishment of a new NK Army Corps (the 10th) two years ago along the frontier with China has been seen by many (including McCreary) as an indication that NK is taking pre-emptive measures against the possibility of a Chinese attempt to establish a buffer zone within Korea in the event of North Korea's collapse. Five of the NK Army's nine regular Army Corps are now stationed in the north in order to provide local and frontier security on or near the Chinese border.
McCreary's thesis for some time now is that if collapse becomes unavoidable, the Kims at least want to go down in history as having achieved the reunification of Korea. After having, in sequence, put satellites into space, and then created nuclear weapons, with each new national achievement having to be greater than the last, and ending with the penultimate express objective, the reunification of the Koreas. The ultimate express objective, of course, is to establish a Communist political system in Korea. But after political unification, that would be a matter to be settled at the ballot box, as unlikely as that may be. These are men that may soon be forced to clutch at straws in order to avoid drowning. It is an interesting thesis, anyway.
Edited to Add:
China doesn't want NK. But as in my previous post, it doesn't want a powerful potential rival right next door either, and on an historic land invasion route no less. If NK collapses, China loses its strategic land buffer in NE Asia against Japan, the U.S., and potentially, South Korea.