I recently enjoyed B.R. Myers' book on DPRK society, although have reservations. He disregards Juche as an interpretation of Marxism-Leninism converging with a Confucianist Korean national culture, and instead points to Japanese colonialism and the racial myths of superiority exported by Japanese nationalists pre-1945 (fascism is still a contested definition for the 1930s) as having a significant influence in shaping DPRK national politics.
Myers is a specialist in DPRK literature, so his novel view involves approaching popular culture in DPRK (both books and film) and what the regime officially sanctions for mass consumption inside the country, rather than the stilted pronouncements the elite make to the outside world. Andrei Lankov is yer man, though, for the specifically M-L side of things.