SEOUL (Bloomberg) - While much remains mysterious about the assassination of Kim Jong Un's half-brother in Malaysia this week, this much is clear: Nearly all of the North Korean dictator's potential rivals are now dead.

In the nation's patriarchal dynasty, Kim Jong Nam, 45, represented a possible alternative if elites ever moved to oust Kim Jong Un, 33. The older brother had lived outside North Korea for years, frequenting casinos in Macau and occasionally criticising his younger sibling's regime.

His only other brother, Kim Jong Chol, 35, isn't seen as a main threat to usurp power.

There was still no mention of Kim Jong Nam's death in North Korean state media as of Thursday morning. At midnight, North Korean leader Kim Jong Un visited the Kumsusan Palace of the Sun to mark the birthday of his father, the late leader Kim Jong Il, who died in 2011.

Malaysian police arrested a female suspect carrying Vietnamese travel documents on Wednesday, and they are looking for others who may be involved. While there's no evidence yet linking the murder to Kim Jong Un, South Korean lawmakers and observers of the secretive regime see him as the clear winner.

"Did Kim Jong Un order the assassination? Yes, almost certainly," said Van Jackson, a former US Department of Defence adviser who now teaches at the Daniel K. Inouye Asia-Pacific Centre for Security Studies in Honolulu.

"He lives a nightmare version of Machiavellian court politics every day, and bloodline is still the strongest claim to legitimate rule in North Korea: Eliminating potential centres of power is cold but shrewd."

The murder has raised questions about the stability of Kim Jong Un's regime as he seeks the ability to strike the US and other potential threats with nuclear weapons. US President Donald Trump has vowed to deal with the threat "strongly" and has called on China - North Korea's prime ally - to do more to pressure the dictator.

Still, pressuring Kim without triggering the country's collapse isn't easy. The Kim family dynasty has ruled North Korea for three generations since its founding after World War II, when the Soviet Union and the US divided up control of the Korean peninsula. Over that time, it has built up one of the world's most vigorous personality cults.

The birthdays of founder Kim Il Sung and his son Kim Jong Il are North Korea's biggest national holidays. The country has held mass propaganda events involving tens of thousands of people to praise the Kim family. Those caught denigrating the country's leaders can be either sent to prison or put to death.

Any minor achievement is hailed by the state-run media, which depict the Kims as geniuses with benevolent hearts. Children are constantly taught about the greatness of the dynasty in school, and statues of Kim Jong Il and Kim Il Sung dot the nation. Their bodies have both been embalmed and placed in a mausoleum in Pyongyang.

Kim Jong Il, who ruled North Korea from 1994 to 2011, is known to have had three sons. He favoured Kim Jong Un the most because his youngest son resembled the dictator in behavior, according to a 2003 memoir by a former Japanese chef for the family. Kim Jong Nam was born to Kim Jong Il's second wife, an actress, while his two other sons were born to his third spouse, a Japanese-born dancer.

Kim Jong Un has routinely conducted purges to consolidate his grip on power, a practice also employed by his father and grandfather. Although there is no great indication that he faces the threat of a coup, that prospect looks even more remote with Kim Jong Nam gone.

'Really Talented Guitarist'

The male-dominated, patriarchal leadership structure all but rules out Kim Yo Jong, Kim Jong Un's sister, as a potential successor. While North Korea's propaganda machine has made no mention of any children, basketball player Dennis Rodman told Britain's Guardian newspaper after a 2013 trip to Pyongyang that Kim Jong Un and his wife have a daughter.

Thae Yong Ho, the former No. 2 at North Korea's embassy in London who defected to South Korea in August, ruled out a potential challenge from Kim Jong Chol in a briefing with reporters in Seoul on Jan 25.

"Jong Chol is not interested in politics at all and doesn't own any official title," Thae said. "He's just a really talented guitarist."

Thae recalled bringing Kim Jong Chol to a music store in London. As he finished playing the guitar, people surrounding them were surprised and asked what professional band he played for, Thae said.

Kim Jong Il saw his middle son as "girlish," according to the former Japanese chef who went by the pen name Kenji Fujimoto.

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 US professional basketball like his brother.

Kim Jong Nam, on the other hand, posed more of a threat. He was caught in 2001 trying to enter Japan using a fake Dominican Republic passport, diminishing his chance of succeeding his father as North Korea's leader.

He reportedly told Japanese authorities that he wanted to go to Tokyo Disneyland.

After Kim Jong Un took power, Kim Jong Nam didn't shy away from criticism. He wrote to Japanese journalist Yoji Gomi that his half-brother's regime "won't last long," South Korea's Chosun Ilbo newspaper reported in 2012.

At some point Kim Jong Nam began spending lots of time in China. He started families in Beijing and Macau and had the protection of Chinese authorities, Lee Cheol Woo, head of the intelligence committee in South Korea's parliament, told reporters in Seoul on Wednesday after a briefing by intelligence officials.

China's foreign ministry said that it's closely monitoring the case.

Whereabouts Unknown

Kim Han Sol, one of Kim Jong Nam's sons, described the North Korean leader as a "dictator" in a 2012 interview with Elisabeth Rehn, a former United Nations undersecretary general from Finland.

Kim Han Sol's whereabouts remain unknown, South Korean Unification Ministry spokesman Jeong Joon-hee told reporters on Wednesday.

Kim Jong Un has had a "standing order" to kill Kim Jong Nam since he took power in 2011, Lee said. After an assassination attempt in 2012 failed, Kim Jong Nam wrote a letter to his brother pleading with him to cancel the order, the lawmaker said.

The following year, Kim Jong Un executed his uncle and one-time deputy Jang Song Thaek, whose wife had helped raise Kim Jong Nam.

While Kim Jong Nam refrained from criticising North Korea after Jang died, he was still a "pain in the neck" because he led a life of luxury and demanded money from his reigning family in Pyongyang, said Cheong SeongChang, who researches North Korea's leadership at South Korea's Sejong Institute.

"Kim Jong Un may have eliminated a thorn in his flesh with the assassination of Kim Jong Nam, but now North Korea faces deeper isolation," Cheong said.

"International isolation raises complaints further among the elite and ordinary people, hurting the stability of his regime."