- North Korean leader Kim Jong Un may have recently underwent heart surgery, and he is rumored to be gravely ill.
- South Korean intelligence has denied the reports, but has been unable to tamp down speculation about who might replace Kim if he dies.
- Kim comes from a line of Communist Party dignitaries and North Korean heads of state that stretches back to the end of World War II, but he doesn't have a clear heir.
- Here's a look at his family tree and the challenges the country faces in determining a successor.
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Rumors are flying about North Korean dictator Kim Jong Un's health and prompting questions about who might succeed him if he dies.
US intelligence reportedly indicates that Kim recently underwent heart surgery and could even be incapacitated. The South Korean government denied the reports, but that hasn't tamped down the speculation.
Few political figures have drawn such intense curiosity as the secretive Kim Jong Un and the people believed to make up his family tree.
Kim has become the face of North Korea to the world in recent years in light of his missile testing and bombastic feuds with President Donald Trump. But he comes from a line of Communist Party dignitaries and North Korean heads of state that stretches back to the end of World War II.
Like his father and grandfather, Kim keeps key details about his family withheld from the public, giving few clues about the lives of his wife and young children. But the penchant for privacy hasn't stopped international media and South Korean intelligence from attempting to learn all they can about him.
Some North Korea observers, such as the American website NK News, have even speculated that it's unlikely a family member would take over, and instead one of the top leaders of the Workers' Party of Korea would step in after a power struggle.
While the world speculates about his health and line of succession, here's a look at the mysterious figures that make up the North Korean leader's family tree.
SEE ALSO: 9 of the most outrageous things Kim Jong Un has said, before his about-face attempt at diplomacy
Kim Jong Un is at the center of a complex and secretive family tree.
The leader of the Hermit Kingdom, like his ancestors, has offered scant information about his family members.
That makes it difficult to ascertain who will succeed Kim if he dies.
Though Kim has one living brother, and possibly two sons, it's unlikely any of them would take over as leader.
Kim is the youngest of three sons — but one is dead, and the other has been deemed unfit to rule.
Though it's typical for the eldest son to become the heir to the title of Supreme Leader, his older brothers — Kim Jong Chol and his half-brother Kim Jong Nam — were bypassed in favor of Kim Jong Un.
Kim Jong Chol is Kim Jong Un's older brother who was supposedly going to succeed Kim Jong Il until he was rejected in favor of Kim Jong Un.
Kim Jong Il reportedly rejected Kim Jong Chol from leadership because "he is like a little girl."
Kim Jong Un is believed to have felt uneasy about his eldest brother, Kim Jong Nam, prompting the widespread belief that Kim Jong Un was ultimately behind the plot to murder him in February 2017.
Kim Jong Nam was the victim of an intricately orchestrated assassination plot, in which two women allegedly attacked him with VX nerve agent, each smearing his face with substances that reacted with one another, causing him to die.
Kim Jong Nam was also the father of three children, whom some have suggested may also be considered a threat to Kim Jong Un's regime.
One of Kim Jong Nam's children bears the seemingly Western name Kim Jimmy.
Kim Han Sol, who is only 22, has spoken out against his uncle's regime, saying in a 2012 interview with Finnish television that Kim is a "dictator" and that he dreamed of going back to North Korea to "make things better, and make things easier for the people back there."
After Kim Jong Nam's death, Kim Han Sol said in a YouTube video that his family feared for their safety.
His younger sister, Kim Yo Jong, is a favored family member who has previously stood in as a proxy for her brother and has been dubbed North Korea's 'most powerful woman.' But it's unclear if the country would allow for a female leader.
Kim Jong Un named her the head of the propaganda department of the Worker's Party of Korea in 2017, and in the years since, she's become his right-hand woman.
She garnered international attention when she represented the regime in a delegation to the Winter Olympics in Pyeongchang, South Korea in February 2018.
She has also played a crucial role in previous diplomatic efforts — at one 2018 meeting in the Demilitarized Zone between North Korean and South Korean leaders, Kim Yo Jong was the only woman at the table.
Though she holds a high-level role, it's unclear exactly how much power she has. She has at times been seen performing subservient, and even humiliating tasks. She once made headlines after she was seen holding her brother's ashtray while he smoked during a train voyage to Hanoi, Vietnam.
Kim is believed to have three young children — but the North Korean government hasn't even confirmed they exist, and all of them would likely be too young to rule.
South Korean intelligence has confirmed that there are three children, the oldest of whom is a boy, and that they were born in 2010, 2013, and 2017.
But it's unlikely a 10-year-old would be tapped to rule the country, and the secrecy surrounding the children would likely pose difficulties in naming one of them as the heir.
The only other publicly known information about Kim's children comes from none other than Dennis Rodman, the former US basketball star who has struck up a controversial friendship with Kim, and who has visited North Korea several times.
Rodman has told media that he once held Kim's second child — a baby girl named Ju-ae.
Little is also known about Kim Jong Un's wife Ri Sol-ju, except what is seen in photos released by the country's state-run media — namely that she accompanies him to public events and has a penchant for expensive designer clothing.
Ri's pregnancies have been the subject of international speculation, generally because she sometimes disappears from the public eye for months at a time.
While people sometimes worry that her absences are because of falling out of favor with her famously impulsive and mercurial husband, South Korean intelligence typically suggests she leaves the public eye when she is carrying a child.
But Kim Jong Un isn't the first to withhold details about his family — his father Kim Jong Il, who ruled from 1994 to 2011, was even more secretive.
Kim Jong Il never even officially confirmed that he had a wife, but he is believed to have married Kim Yong Suk around 1994, and maintained several other extramarital relationships, one of which yielded Kim Jong Un.
Kim Jong Il has a sister named Kim Kyong Hui, who was also active in North Korea's politics but has remained largely hidden from the public eye.
Now 72, she is apparently being treated for a host of deadly diseases, and disappeared from public view in December 2013.
Part of the reason for Kim Kyong Hui's disappearance was Kim Jong Un's execution of her husband, Jang Song Thaek.
Jang Song Thaek was allegedly plotting to overthrow the regime in 2013, after which he was given the death sentence by his nephew, Kim Jong Un.
Kim Sul Song is one of Kim Jong Il's children and Kim Jong Un's 40-year-old half-sister, and is a powerful business magnate in North Korea
Although she has been rumored to be one of Kim Jong Un's rivals due to her powerful position, she has since rallied around her half-brother after Kim Jong Il's death, and now sits in the upper brass of North Korea's political class.
Finally, the common root of this entire maze of family relationships is Kim Il Sung, Kim Jong Un's grandfather, who is considered the founding father of North Korea.
Born in 1912, Sung was a guerilla fighter battling the Japanese occupation of Korea, and later fought with the Soviet Union during World War II.
He was able to consolidate power over what became North Korea immediately after the war, and although he was only officially elected president in 1972, had effectively held power over the state as premier ever since 1948.
Kim Il Sung led North Korea from the regime's inception in 1948 to his death in 1994. He married twice, but just like his grandson, it's not entirely clear how many children he had.
It's believed he had two children — including Kim Jong Il – with his first wife, Kim Jong Suk, and three children with his second wife, Kim Song Ae. He is also believed to have had other children from extramarital relationships.
What started with Kim Il Sung's small nuclear family of four has evolved into a longtime political dynasty. Now that the Kims are in possession of nuclear weapons, they are among the most famous families in the world.
Now that Kim's health has potentially thrown a wrench in the family's grip over the country, all eyes will be watching to see the power struggle that could ensue if Kim, indeed, dies before naming an heir.