How did the cult of personality evolve in North Korea? Quickly in some ways, slowly in others, and perhaps not at all in some. We don't actually know the degree to which the average North Korean uncritically swallows the Kim regime's propaganda.

But let's start with the basics!

What are North Koreans asked to believe? North Koreans are reared from birth to honor Kim il-Sung, the once-leader and now "Eternal President" of their nation. He is the greatest military hero of the Korean people, having single-handedly saved Korea from the ravages of the Japanese empire. He was also an artistic genius, having penned several operas that are performed to this day. His generosity of spirit and smiling benevolence were second to none; he was the reason that North Koreans had food, clothing, toys, jobs, and homes. He held the nation together and successfully defended it against the wolflike Americans. When he visited factories and workplaces, prosperity flowered in the wake of his impeccable advice. His son Kim Jong-il, while undoubtedly a lesser light, showed the power and strength of the bloodline! At his birth on the sacred Mount Paektu, soldiers carved prophecies of his eventual greatness onto the nearby trees. He fired at retreating Japanese soldiers at the age of three. Kim Jong-il would go on to become one of the world's greatest film directors and critics, a peerless minister to the people, and tender shepherd of the nation through its Arduous March, which he and his father totally didn't cause. Portraits of the Kims are to be hung and cared for in each home and workplace as a reminder of the family's guardianship of the Korean people. Bonus points to anyone who dies protecting one! Pins of one or both Kim il-Sung and Kim Jong-il are to be worn for the same reason.

And so on, and so on ... there's actually quite a lot more that could be written about this. We've barely scratched the surface.

To be clear, personality cults are nothing new. They date to the earliest forms of complex human government and were an inescapable part of absolute monarchies. Even in modern democracies, successful politicians get some mileage out of very mild forms of it. (Though I'm sure some stick-in-the-mud historians who are just no goddamn fun would disagree that the cultural impulse behind the god-kingship of the pharaohs ≠ Obama-Biden memes.) However, personality cults evolved and enjoyed a renaissance during the 20th century, particularly in Soviet-aligned states, and the Kims were far from being the only beneficiaries. What was unique about the North Korean version was its incredible strength and longevity. It's so grotesque and laughable to outsiders that it's inevitably one of the features that attracts Western attention to NK.

However, historians have a pretty decent handle on how and why it developed the way it did:

• Korea was already primed to seize on a figure of heroic importance: There was increasingly bad blood between Korea and Japan in the late 19th and early 20th centuries for a lot of reasons. We'll condense what's actually a fascinating and complicated subject for the sake of speed: Korea was the subject of interest from China, Russia, and Japan, with the latter emerging victorious in a vicious game of influence and force (including the assassination of the Korean empress in 1895). The Japanese empire made Korea a protectorate in 1905 and then annexed the peninsula five years later. It remained in control of Korea until the end of World War II, when Hirohito decided to take it on faith that the Americans weren't bullshitting about having a third atom bomb. (Spoiler alert: The Americans were bullshitting about having a third atom bomb, at least until two days after Japan surrendered.) The average Korean did not particularly want to be under anyone's thumb, and was even less interested in being under Japan's thumb; there was greater popular, and certainly official, sympathy toward Russia. Korea's colonization left behind a humiliated and resentful people -- one that was very susceptible to fierce nationalism with an appealing figurehead.
• The Soviet Union was interested in placing a controllable person in charge, and a lot of experience with personality cults and propaganda. Stalin's personality cult is way outside the scope of this comment, but suffice it to say that the Soviets knew how to mobilize government and the media on behalf of a leader. The Soviets moved down into the northern half of the Korean peninsula in September of 1945, and traveling with them was a 33-year old Kim il-Sung. The occupation authority was already disposed to like him because he was a committed Communist, had been with the Red Army for roughly five years already, and needed an awful lot of help (see below).
• Kim was well-placed to assume the two-part role of "Appealing figurehead and "Controllable person in charge." Whatever else you could say about Kim, he had fought against the Japanese occupation, and he was a big, handsome man with bonafide nationalist credentials. The Soviets eagerly trotted him out in front of a crowd to give a speech. Left unsaid was that: a). he'd fought as part of a Chinese-led army (the Northeast Anti-Japanese United Army): b). He wasn't among the most important or effective officers in it, but: c). He was decent enough that the Japanese got tired of dealing with him and put a price on his head, so: d). He ran like a spanked cat to Siberia and spent the entirety of World War II sitting on his butt and being a huge dick to his translator: e). when he returned with the Soviets, he'd been out of Korea for decades and spoke Chinese better than Korean, so: f). Soviet-Koreans had to write his speech for him and coach him on pronunciation and grammar. When he finally gave the speech, the crowd barely understood him because he spoke with a thick accent. But propaganda has never lingered overlong on the truth, and subsequent North Korean accounts of this scene depict it as an utterly triumphant return to wild, cheering crowds in Pyongyang.
• Kim and the Soviets had a symbiotic relationship, each benefiting from playing the other up: After the Soviets' first pick got too obstreperous, Kim got the nod to lead the provisional government. The Soviets went into overdrive equipping the nascent North Korean military and pushing propaganda on Kim's behalf. Put simply, they needed each other. Kim needed them (and particularly an educated group of Soviet-Korean and Chinese-Korean bureaucrats) for equipment, advice, organization, and protection: The Soviets needed him to legitimize their presence and influence on the peninsula, and to provide a bulwark against the American-controlled south. North Korea had the peninsula's only land crossings into both China and the USSR, and a set of warm-water ports; isolating the Americans was a happy side effect. The Soviet-Korean and Chinese-Korean contingents borrowed heavily from elements of both Stalin and Mao's personality cults in this period, and if you've studied either, it's impossible to escape a sense of déjà-vu while studying Kim's. (Soviet and Chinese exchange students would later have great fun pointing out all the parallels among statues, iconography, and parables to horrified North Koreans.)
• The exile of the once-helpful bureaucrats and the development of the camp system: Time skip here, as the Korean War in the intervening period put some brakes on the advancement of the personality cult (Kim was probably at his most politically vulnerable then, and might not have survived in power if the Chinese hadn't pulled his chestnuts out of the fire). The group of Soviet- and Chinese-Koreans who had been so crucial to the development of the North Korean state had outlived their usefulness by this point in more ways than one. They knew the degree to which Kim's heroic background had been absurdly exaggerated, that Kim had never conducted a guerrilla campaign against the Japanese from Mount Paektu, and how much Soviet and Chinese aid masked his poor decisions. Kim forced them out of power and subsequently out of the country once he had a sufficiently-pliant set of military friends installed in the government around the mid-1950s. He rethought this upon the realization that political enemies sent into exile had passed entirely outside of his control, and we think the North Korean camp system began to develop in the postwar period. Some camps were definitely in place no later than 1958. The camps didn't help the personality cult in themselves; what they did do was create a convenient way for Kim to ship potentially problematic people and their families out of positions from which they might have wielded influence. Fortunately for Kim, he was able to do this before Khrushchev started making a real pest of himself demanding that states within the USSR's sphere of influence got rid of embarrassing personality cults. Increasing antagonism between China and the USSR at the time (the Sino-Soviet split) helped too. Soviets pissed at you? Run to the Chinese. Chinese pissed at you? Run back to the Soviets. Both of them pissed at you? Whatcha gonna do about it with the Americans lying in wait on the other side of the DMZ? (Answer: Nothing. Kim had them over a barrel there.)

However, if I had to pick any one element as the most influential -- or at least, the one in which the personality cult started to assume the bugfuck crazy form in which it exists today -- it'd be the power struggle over succession in the mid-1960s to mid-1970s.

More below!

This is a very complicated subject to discuss, but to simplify, we'll start back at the end of WW2.

Since 1910, the Korean peninsula had been under Japan's imperial rule, but when Japan surrendered to the Allies, they left Korea, and this is when it all began.

The Soviet Union and America entered the Cold War, and each sought power wherever they could in the world. When Korea finally regained its independence, the Soviets and Americans saw an opportunity to gain a piece of allied territory.

Each wanted Korea in their image, but instead of starting a full-scale conflict over it, they decided to split the country (arbitrarily) at the 38th parallel.

The Soviets wanted a communist regime, so they wanted a leader they had some sway over. They needed whoever they chose as leader to be popular among Koreans but also trustworthy and loyal to the Soviets. Kim Il-sung, a guerilla leader who fought for the Soviets in WW2, fit the bill, and installing him was surprisingly easy because he was seen as a Korean patriot worthy of respect among the people.

At this point, we'll zoom out briefly to explain the larger dynamic. All you really need to know is that the Soviets were apparently better backers than the Americans, and for a time, it looked as though NK would win the entire peninsula.

America was unhappy with this, and they got the UN involved to help push the North Koreans back. But instead of leaving it at that, they proceeded to bomb the hell out of North Korea. (Estimates suggest American bombs are responsible for killing 20% of NK's population at the time.)

China eventually stepped in (because the fighting was getting too close to the NK-China border) and helped NK fight the Americans back to the 38th parallel. This is where the war has been since 1953.

So now we get back to NK. The destruction wrought by America had devastated the country. North Koreans hated and feared America, and Il-sung used this to his advantage. He created a narrative where the American threat was ever-present—unless the people allowed him absolute control.

Il-sung devoted his country and its resources to preparing for another attack by America, and for the next few decades, this is how the country operated. The country became more militarized, and they started as a nuclear power, all while controlling all aspects of civilian life, from food to wares to information.

Il-sung knew how to control people by playing on their fears and their dreams. He used these fears and dreams to justify everything he did. But to ensure that people could go along with his totalitarian rule, there needed to be a massive propaganda campaign calling for unflinching support of Il-sung. Through the years, the campaign became more aggressive. There was a true love of Il-sung among the people, but it's hard to know how far that loves goes and how much is political and social pressure to keep up your appearances of praise for Il-sung.

So in the end, Il-sung was a trusted patriot who saw the country through the horrible war against America, and seemed to devote the rest of his life and his country's resources to defending his people from another American attack. This was all concomitant with the propaganda campaign that gushed over how incredible and competent he was, all part of the plan to ensure he could do whatever he wanted with the country.

And this is the end of Il-sung's story. He died in 1994, at which point his son came to power. But his son also came into power under difficult circumstances: the Soviet Union had collapsed three years earlier. Without any Soviet aid, things were starting to fall apart in NK, which was in stark contrast to the flourishing country to the south.

So Kim Jong-il made a drastic play. Since his country looked bad on the inside, he decided the rest of the world must be made to look bad as well. This was done by stifling all information from the outside world, an extension and expansion on what his father had done.

Now at this point, Jong-il was the head of a failing communist state that was telling its people they were the luckiest and most well-off people in the world, and this lie got out of hand. They even have a popular NK song, which translates to, "We have nothing to envy in the world." For a long time, few people knew anything about how the rest of the world was doing.

The only real choice was to dial up the propaganda to 11, and a lot of what is said about Il-sung now actually came after his death where he was further idolized by his son and the government. The best response to keeping their government intact despite the desperate living conditions of their people was to constantly push how special and powerful their leaders were while also suppressing outside information on the prosperity of the rest of the world.

Jong-un did nothing more than repeat this behaviour, and at some point, the propaganda machine deemed them the "divine beings" we know today. The evolution was, oddly enough, arguably the only thing they could have done if they wanted to keep their power without changing their entire country's ethos.

Tl;dr: public fears of American attacks were used to justify and fuel a propaganda machine that illustrated the power, competency, and divinity of the Kim family as the country fell into increasingly difficult times.