Okay, well, if you feel like reading a book sometime, I highly recommend Patriots, Traitors, and Empires: The story of Korea's Struggle for Freedom, by political analyst Stephen Gowans (he's not a commie, no reason to be scared)(edit: he's a marxist), it goes into the history of the Korean peninsula, starting from the Japanese colonization in the early 1900s, through WW2, the division of the country into North/South, the Korean war, through to present day, answering why North Korea (DPRK) is where it's at today.

Here's an article that goes over the basics of it all, if you're not up for reading the whole book (but it's a very good book)