(Bloomberg) -- The mystery surrounding Kim Jong Un’s health exposes deep uncertainty about North Korea’s line of succession more than eight years after he took power.

While the Kim family has ruled for seven decades by passing power between male heirs like other hereditary dynasties, the 36-year-old Kim has named no successor. His own children are still young and the ruling family’s surviving adults all face potential barriers to their rise.

Here are some possible successors:

Kim Yo Jong, Sister

Part royal representative, part personal assistant, Kim Yo Jong, 30, has emerged as one of her older brother’s closest aides. Earlier this month, she was reinstated as an alternate Politburo member of the ruling Workers’ Party of Korea. As such, she’s the only other offspring of Kim Jong Il with anything approaching real power in the regime.

Will a Woman Run North Korea? Kim’s Sister Outshines Male Rivals

Although she became the first member of the ruling family to visit Seoul and accompanied Kim Jong Un in his summits with U.S. President Donald Trump and China’s Xi Jinping, she’s also performed mundane tasks, such as helping the leader extinguish a cigarette during a train stop in China. Whether North Korea’s patriarchal elite will support a relatively young woman as the country’s next “supreme leader” is unclear.

Kim Pyong Il, Uncle

As the last surviving son of state founder Kim Il Sung, Kim Pyong Il, 65, has long been an also-ran in Pyongyang’s power struggles. He has been effectively sidelined since the 1970s when he began a series of foreign diplomatic postings, including in Hungary, Bulgaria, Finland, Poland and the Czech Republic. His name nonetheless re-emerges whenever succession questions arise.

Kim Pyong Il’s retirement and return to Pyongyang last year thrust him back into the mix as a potential compromise candidate to replace his nephew. Still, it’s unclear whether he has any support within the leadership. He was once considered a rival to Kim Jong Un’s father and has been conspicuously absent from decades of state media reports. There have been unconfirmed reports he is now under house arrest.

Choe Ryong Hae, Official No. 2

Choe Ryong Hae -- North Korea’s ceremonial head of state and No. 2 leader -- could be another compromise or caretaker candidate, if the country’s power brokers take the uncertain path of choosing a leader from outside the Kim family. As a member of the Politburo Standing Committee and a former military official who has risen under Kim Jong Un, Choe, 70, has connections to the state’s main power centers.

Perhaps more importantly, Choe’s son may be married to Kim Yo Jong, Washington Post journalist Anna Fifield wrote in her 2019 biography of Kim Jong Un, “The Great Successor.” The North Korea monitoring site NK News described him as the “most realistic” replacement from among the three-member Standing Committee. Choe was thought to have fallen out of favor and got sent for re-education in 2015, but returned to power a few months later, South Korean media reports said.

Kim Jong Un’s Son

A male heir would provide the most conventional line of succession in a dynasty previously ruled by Kim Jong Un’s father and founded by his grandfather. South Korean intelligence said Kim married Ri Sol Ju, a former singer, in 2009 and is thought to have three children.

Problem is, the children have yet to be officially mentioned in state media and the oldest is believed to be a son born in 2010, according to South Korea’s DongA Ilbo newspaper. Dennis Rodman, the offbeat former basketball star who visited North Korea, said in 2013 that he also held a baby daughter named Ju Ae. That would likely require any of the children to rule under some form of regent until they come of age.

Kim Jong Chol, Brother

Kim Jong Chol, Kim Jong Un’s only surviving brother, would be another longshot, since he has shown more interest in guitars than politics. Thae Yong Ho, the former No. 2 diplomat at North Korea’s embassy in London who defected to South Korea, once said Kim’s 38-year-old brother “doesn’t own any official title” adding he’s “just a really talented guitarist.”

Kim Jong Il saw his middle son as “girlish,” according to the person who goes by the pen name of Kenji Fujimoto and claims to have been the personal sushi chef for the former North Korean leader. In 2011, South Korean broadcaster KBS captured Kim Jong Chol enjoying an Eric Clapton concert in Singapore. Little else is known about him except that he studied in Switzerland and is a fan of U.S. professional basketball like his brother.

Kim Han Sol, Nephew

Kim Han Sol, born in 1995, may have become heir-apparent himself if his father, Kim Jong Nam, hadn’t fallen out with Kim Jong Il and gone into exile in the Chinese gambling hub of Macau. Kim Jong Nam was Kim Jong Un’s older half-brother and his most serious rival, frequenting casinos and occasionally criticizing his younger sibling’s regime.

Any hopes that Kim Han Sol might have had of returning to Pyongyang were dashed in 2017, when his father was murdered at the Kuala Lumpur airport by two women who smeared VX nerve agent on his face. Chinese police later arrested several North Koreans dispatched to Beijing on suspicion of plotting to kill Kim Han Sol, South Korea’s JoongAng Ilbo newspaper reported at the time. His whereabouts remain unknown.

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