On Tuesday, after more than a decade in exile from the North, Jong-Nam -- the 45-year-old half-brother of current leader Kim Jong-Un -- was widely reported by South Korean media to have been assassinated in Malaysia.
There has been no official confirmation.
Born from his father's relationship with actress Sung Hae-rim, Jong-Nam is known to have been a computer enthusiast, a fluent Japanese speaker and a student in both Russia and Switzerland.
He lived in Pyongyang after finishing his overseas studies and was put in charge of overseeing North Korea's information technology policy.
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But the chubby eldest son of the supreme leader was already seen by Seoul experts as something of a political lightweight when in 2001 he fell out of favour.
He was embarrassingly detained at a Tokyo airport, trying to enter Japan to visit Disneyland on a false Dominican Republic passport, accompanied by two women and a child.
Jong-Nam and his family afterwards lived in virtual exile in Macau, Singapore and China.
Jong-Nam's half-brother Jong-Un took over as North Korean leader when their father died in December 2011.
In an email exchange with a Japanese journalist published in 2012, Jong-Nam spoke disparagingly of Jong-Un, saying he lacked "any sense of duty or seriousness" and warned that bribery and corruption would lead to North Korea's eventual collapse.
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In another exchange with the same reporter in 2012, Jong-Nam said: "Anyone with normal thinking would find it difficult to tolerate three generations of hereditary succession."
In October 2012 South Korean prosecutors said a North Korean detained as a spy had admitted involvement in a plot to stage a hit-and-run car accident in China in 2010 targeting Jong-Nam.
In 2014 Jong-Nam was reported to be in Indonesia -- sighted at an Italian restaurant run by a Japanese businessman in Jakarta -- and was said to be shuttling back and forth between Singapore, Indonesia, Malaysia and France.
In 2012 a Moscow newspaper reported that Jong-Nam was having financial problems after being cut off by the Stalinist state for doubting its succession policy.
The Argumenty i Fakty weekly said he was kicked out of a luxury hotel in Macau over a $15,000 debt.
Jong-Nam's son Kim Han-Sol studied at university in Paris. Back in 2012, when at school in Bosnia, he labelled his uncle Kim Jong-Un a "dictator" in an interview.
"My dad (Jong-Nam) was not really interested in politics," Kim told the interviewer when asked why his father was passed over for the dynastic succession in favour of his younger brother.
