As a communist nation, North Korea is officially non-religious.
Reference: North Korea | Facts and History
Technically, they're not communist. They never even got close to that stage and have dropped that pretense, anyway. North Korea is probably best described as a corrupted monarchy with a very strong cult of personality.
North Korea is a self-described Juche (self-reliant) state,[97] described by some observers as a de facto absolute monarchy[98][99][100] or "hereditary dictatorship"[101] with a pronounced cult of personality organized around Kim Il-sung (the founder of North Korea and the country's only president) and his late son, Kim Jong-il. However, the 4th Conference of the Workers' Party of Korea said that Kimilsungism-Kimjongilism was "the only guiding idea of the party".[102]
A North Korea scholar dismisses the idea that juche is North Korea's leading ideology, regarding its public exaltation as designed to deceive foreigners.[103] In the latest version of the North Korean constitution, the state and party officially rejected North Korea's founding ideology of communism.[104]
Research based on North Korea's domestic documents, and popularized in 2009 by Brian R. Myers in his book The Cleanest Race, and later supported by other academics,[105][106] characterizes North Korean ideology as being a racialist-focused nationalism, and heavily influenced by the racialist outlook of Japan before the end of the Second World War.[107][108] Charles K. Armstrong criticizes Myers for taking the Japanese comparison too far, suggesting that North Korean ideology is "actually closer to European fascism" than to Imperial Japanese fascism, since Imperial Japan lacked a charismatic leader and mass-mobilizing party.[109]