I think North Korea is getting ready to pick a fight. In fact, they've already picked it. Unless the United States launches a warning strike, I think North Korea will continue to push the boundaries until it gets what it wants. However, what they want exactly still is a question I can't find the answer to.
I am in the military. I hear the whisperings and never is it North Korea. We want nothing more than a war with them to crush their forces easily and swiftly as it's hard to fight for a host country you have no intent to stay in. The second NK leaves its borders, half their forces would defect. Everything NK does is just showboating and posturing.
There is little to no chance that North Korea will attack South Korea for the United States in the near future. To do so what are you sure it's complete and utter destruction. While South Korea is fond of political posturing, its actions are nothing more then schoolyard bullying tactics.
North Korea is not likely to attack either South Korea or the United States. The country has made a lot of threats, especially in light of increased sanctions. However, if North Korea were to launch an attack, it would face massive casualties from its better armed neighbors and the United States.