As the first son of Kim Jong Il, the late leader of the Democratic People’s Republic of Korea, Kim Jong Nam always posed a threat to Kim Jong Un, his half brother and North Korea’s current leader. Before falling out of favor with his father and going into exile soon after, paving the way for Kim Jong Un’s ascent, Kim Jong Nam was the heir apparent. With the execution in 2013 of Jang Sung Tak, the second in command and the eldest son’s staunchest supporter, Kim Jong Nam was unprotected, with little hope of ever returning home.

On February 13, Kim Jong Nam was murdered in Kuala Lumpur airport by two hired killers. The fascination surrounding the killing has centered on its sensational circumstances: that one of the killers smeared a poisonous toxin, reportedly VX gas, across Kim’s face; that one of them wore a T-shirt with the acronym “LOL” printed across the front; that the other reportedly mistook the hit for a comedy stunt. Malaysian police have detained five people allegedly connected to the killing, and remain on the hunt for others—including several North Koreans—linked to it.

The identification of the chemical agent used in the attack could very well suggest a deeper connection to the Kim Jong Un regime, which is believed to have amassed a stockpile holding anywhere from 2,500 to 5,000 tons of chemical weapons, including VX gas. (North Korea denies the existence of a chemical weapons program.) If Kim Jong Un ordered the hit, a theory the South Koreans have endorsed, it will have proven a senseless, brutal, desperate act, but not an uncommon one for the 33-year-old Great Leader. After taking over from his father in 2011, Kim Jong Un systematically removed many of the country’s top officials, including the 67-year-old Jang, an uncle by marriage, who was executed for alleged treason. Sanctioning such a killing was certainly sacrilegious, particularly in light of the 5,000-year-old Korean tradition’s Confucian reverence for family. But in the dictatorship of North Korea, built around the absolute power of the Great Leader, Jang’s killing wasn’t all that surprising.

The killing of Kim Jong Nam, however, is different. Unlike Jang, Kim Jong Nam had royal blood coursing through his veins, given his direct line of descent from North Korea’s founding leader Kim Il Sung.

The foundation of North Korea is largely built on a tradition of ethno-centric nationalism, whose origins date back to the Confucian Korean monarchy as well as to Japan’s colonization of Korea from 1910 to 1945. The purity of bloodline dictates who will rise and who will fall. In 2011, when I lived in North Korea undercover to teach the sons of the elite, most of my students came from the top of the sungbun caste system, which ranks North Koreans according to family history and loyalty to the government. The lower classes are designated for those with family roots in South Korea or Japan, both archenemies of North Korea. In many ways, the sungbun system exists to sanctify the Great Leader as a sort of God-parent, embodying monarchy while yielding legitimacy to the cult of pure blood.

Indeed, North Korea’s founding mythology is inseparable from that of the Great Leader. In most descriptions of Kim Jong Un in official North Korean communications, the phrase, “Baekdu hyultong,” or Baekdu bloodline, appears. This is a reference to Mount Baekdu, the tallest mountain on the Korean peninsula, a potent symbol of Korean nationalism, and a spiritual home for Koreans on both side of the 38th parallel. From an early age, North Koreans are taught that Kim Il Sung, the grandfather of Kim Jong Un, commanded anti-Japanese guerrillas from a secret camp in Mount Baekdu during the Korean War. They are also taught that Kim Jong Il, the previous Great Leader, was born there (in reality, he was born in Russia) after receiving its holy energy.

The average North Korean is thus steeped in the myths of three generations of Great Leaders. Every citizen studies the lives of the Kims, watches television programs and reads newspaper articles solely about them, wears badges displaying their faces, and celebrates the birthdays of the two dead men, Kim Il Sung and Kim Jong Il, as the Day of the Sun and the Day of the Shining Star (Kim Jong Un’s birthday, which will reportedly be known as the Day of the Galaxy, has not yet been declared a national holiday, possibly to avoid drawing attention to his youth). Fealty to these Great Leaders, the carriers of the Baekdu hyultong is, in most respects, a tightly controlled, fundamentalist religion.

Perhaps in adherence to this holy bloodline, Kim Jong Il himself never (to our knowledge) engaged in family killing, settling instead for banishing his rival and half brother, Kim Pyung Il, who has spent most of his life in exile abroad, first as an ambassador to Poland and now the Czech Republic.

Kim Jong Un is perhaps uniquely dependent on the myth of Baekdu hyultong. Unlike his father, who spent decades as an heir to his grandfather, Kim Jong Un spent the bulk of his formative years in Switzerland. He inherited power with little preparation, and without a hallowed reputation. It was in the final years leading up to his father’s death in 2011 that Kim Jong Un was hastily ushered into the role of successor, but even that year when I lived there, my students rarely ever mentioned him in conversations. At the age of 33, Kim Jong Un is too young to pull off a convincing God-parent image of the Great Leader who oversees his people. The same goes for one of his official titles as the Supreme Commander of the Korean People’s Army. There is also some question as to his own heritage, which is kept secret within North Korea. His now-dead mother, Ko Young Hee, a mistress of Kim Jong Il, was born in Japan, and is believed to come from a Korean-Japanese background, which would make her son’s own heritage “impure,” slotting him into the lowest sungbun class. The other strain of Kim Jong Un’s heritage, his Baekdu bloodline, is just about the only thing that secures his place as the Great Leader.

With the untimely death of Kim Jong Nam, the most direct heir to Baekdu hyultong, its Godlike power is now broken, creating room for others seeking to defy its sanctity—perhaps by targeting the Great Leader himself, now exposed as a mere, replaceable mortal. Nor does Kim Jong Nam’s murder erase other rivals of the Baekdu bloodline who could challenge Kim Jong Un: namely his nephew Kim Han-sol, the 22-year-old son of Kim Jong Nam, and his other siblings, Kim Jong Chul and Kim Yuh Jung.

Kim Jong Un’s reign of terror suggests an escalating paranoia, which goes hand in hand with the fear at the root of North Korean society. Yet, for the first time in North Korean history, that very paranoia may have cracked the foundation of his own legitimacy, opening the door to the possibility of the end of the Baekdu bloodline. In that case, the murder of Kim Jong Nam would have been a self-sabotage of the highest order.