Andy Jackson highlights two contingencies the Brilliant Comrade, Kim Jong-un, needs to consider, the second of which involves sibling rivalry in the dim reaches of the Kim clan. But, I do have to point out a third prospect.
There are at least two points in the first few years after Kim Jong-il dies that could lead to instability.
The first is early on, before when various groups compete to be the power behind the throne. The various factions, including the military, party officials and members of the extended Kim clan attempt to flatter, cajol or force their way into the successor’s inner sanctum in a bid to become puppet masters to an isolated monarch. That would be especially tempting for female members of the Kim clan, more distant relatives or in-laws.