SEOUL - Mount Baekdu, which straddles the China-North Korean border, is the highest and most sacred mountain on the Korean peninsula.
It is the place where North Korean founding leader Kim Il Sung fought Japanese occupation forces, and where his son Kim Jong Il was born.
At least that's what North Koreans are told to believe.
The so-called "Mount Baekdu bloodline" is used by the Kim family to legitimise its iron-fist rule in North Korea for the past seven decades. Sadly, the blood ties is also the most probable reason why Kim Jong Nam, 45, was killed in Kuala Lumpur on Feb 13.
The eldest of Kim Jong Il's three sons, Kim Jong Nam was born in 1971 to famous actress Song Hye Rim. His birth was kept a secret for many years because his grandfather Kim Il Sung disapproved of the relationship.
Ms Song was a divorcee of South Korean descent. She was born in the south-east of the Korean Peninsula during Japanese colonial rule and followed her parents to the North during 1950-53 Korean War.
She was kept away from Jong Nam whose main caregivers were his maternal grandmother and maternal aunt Song Hye Rang.
Jong Nam had a lonely childhood. He was often confined behind walls with guards watching his every move. His aunt said he could be moody at times and had a short temper.
Even so, he was the apple of his father's eye and deemed to be the heir apparent.
"Kim Jong Il doted on his son - sleeping with him, eating dinner and telephoning him when he was too busy to return home," said North Korean leadership expert Michael Madden, a visiting scholar at Johns Hopkins University.
Every year on his birthday, Jong Nam is known to put on a military uniform and win "promotions" by his father. By age seven, he was already a top-ranked "marshal".
When Jong Nam turned eight, he was sent abroad to study in Russia and Switzerland. His father started a new family and channelled his love for his eldest son to his new children, including youngest son Jong Un.
Jong Nam returned to Pyongyang when he was 18 and found himself trapped in a life of misery and captivity.
"It was very difficult for Jong Nam to feel free, as his father kept him under surveillance," Song Hye Rang wrote in a memoir published after she defected to Geneva in 1996.
"The feeling of emptiness grew stronger and stronger with each passing year, because Secretary Kim Jong Il had already left the house and was abandoning Jong Nam whom he had dearly loved," she wote in a translated extract of the memoir published on the North Korea Leadership Watch website, which is maintained by Mr Madden.
In 2001, Jong Nam grabbed international headlines after he was caught entering Japan on a fake passport in 2001.
Apparently it was the last straw for his father, because following that embarassment Jong Nam was banished to a life of exile in Macau where his second wife and children live. His first wife and their son live in Beijing.
Contrary to reports which said Jong Nam fell out of favour with his father over the passport incident, Mr Madden told The Straits Times that the two had kept in contact until the last months of Kim Jong Il's life.
"As in many parent-adult child relationships, they certainly had conflicts and arguments. However, he was never cut off from contact or support from his father."
Jong Nam was known to have travelled extensively to South-east Asia, where he reportedly kept mistresses and engaged in illicit business activities, and Europe, where his eldest son was studying.
He became media fodder and had a reputation of being a playboy and connoisseur of fine wines, lavish restaurants, luxury hotels and fancy casinos.
Twice he was spotted at Singapore's Marina Bay Sands.
But in the secretive North, ordinary North Koreans are not even aware that he existed.
A North Korean defector told The Straits Times last week (Feb 25) that before he escaped to the South in 2010, he had never heard of Jong Nam or his half-brother Jong Un.
The latter took power in late 2011, after the death of their father Kim Jong Il.
"The Kim family is God, but there are strict rules to follow. If you ask too much about the Kim family, you can be killed," the defector said on the condition of anonymity.
But Jong Nam was not someone to mince his words.
In 2010, a day before his younger brother was to make his first appearance as heir apparent in North Korea, Jong Nam told Japan's TV Asahi that he was "opposed to third-generation succession".
In interviews with Japanese journalist Yoji Gomi, who would later publish a book about their exchanges, Jong Nam called Jong Un a "nominal figurehead" and said the North Korean regime would collapse without reform.
"Even if it put him in danger, he wanted to tell his opinions to Pyongyang through me or other media," Mr Gomi said at a press conference held in Tokyo not longer after Jong Nam's death.
The talk is that Beijing had been offering protection to Jong Nam as an alternative heir to the North Korean regime in case Jong Un was dethroned.
Given China's history of invading Korean dynasties and interference with politics on the Korean peninsula, this could have deepened anxieties in Pyongyang about Beijing's true intent.
The two brothers were raised separately and met only once - during the private funeral of their grandfather Kim Il Sung in 1994.
In the wake of Jong Nam's murder, attention has shifted to his first-born and eldest son Han Sol.
"Where is Kim Han Sol?" is a question that has kept the media abuzz, especially after Malaysian authorities called for Jong Nam's next-of-kin to provide a DNA sample for identification of his body.
Han Sol, according to South Korea's spy agency, is in Macau - under Chinese protection.