I am not certain just speculating based on my understanding of (1) China's historical stance on issues affecting the Korean peninsula and (2) my understanding of the military's role in Kim Jong-il and Kim Sung-il's regimes.
China is N. Korea's only ally and benefactor. I don't remember the numbers but the aid NK receives from China is significant. Essentially, without it, N. Korea's economy would suffer a catastrophic collapse making the recent famine seem like boon times. China supports NK simply b/c, without it, a united Korea under the Republic of Korea (South Korea) places a US/Western ally on their Manchurian border. Essentially, China views NK as a necessary buffer state and that's why they pump resources into it. Based on this, I would expect China to have a significant role in determining the political future of NK.
As to the NK military, it has a 1,000,000 million man army with 8,000,000 active reserve.
Military Strength of North Korea. Additionally, as with most dicatators, it is the Praetorian Guard that made Jong-il's autocratic rule practicable. Given its size and historical role in the regime, I am simply speculating that it has some serious power players within it who will expect a significant voice in the country's affairs.
In addition to all that, my wife's best friend is a NK double agent who keeps me in the know.