Kim Jong-un and his recently killed brother might both have competed to be the supreme leader of North Korea but in the end they both ended up having wholly different lives and holding divergent political perspectives.

According to South Korean media reports, the North Korean leader’s brother, Kim Jong-nam, has been attacked by two women with “poisoned needles” at Kuala Lumpar airport in Malaysia. The two women, believed to be North Korean agents, are reported to have immediately fled the scene in a taxi.

If reports are true, this could be the most significant killing of a member of North Korea’s ruling family since the death of Jang Song Thaek in 2013.

Mr Kim, the supreme leader’s half-brother who is the eldest son of Kim Jong-il, has spent far less time in the limelight than his younger brother who he is believed to have never met. The 45-year-old went into hiding in Malaysia after Mr Jang, his powerful uncle and guardian, was brutally executed in December 2013.

Mr Kim, who survived an assassination attempt in Macau in 2011, was formerly the current leader’s rival heir to the country but he fell out of favour in the Hermit Kingdom and moved overseas, living in Macau, China, Singapore and, Malaysia.

But who is the estranged brother, who has been dubbed a playboy for his reported gambling and extravagant spending, and why has his life been so different to that of his brother?

He was educated in Switzerland

He was the non-marital son of Song Hye Rim, a North Korean actress who was with Kim Jong Il and one of three women known to have had children with the former leader.

According to Yoji Gomi, the author of My Father, Kim Jong Il, and Me who met with Mr Kim for interviews in Macau and Beijing several years ago, he said the half-brothers were kept apart because of an age-old history of raising potential leaders separately.

Mr Kim was born in Pyongyang in 1971 but was educated in Switzerland, prompting his father to later reportedly consider he had turned “into a capitalist”.

According to Gomi, it was his Swiss education which convinced him North Korea was in need of embracing economic reforms.

Interestingly, his half-brother, the current North Korea leader, was also educated in Switzerland but developed no such opinions.

North Korean leader Kim Jong-Un delivering his new year message in Pyongyang (Getty)

He was the former heir to be leader

If things had gone differently there is a chance the lesser-known of the two brothers could have been the leader of North Korea. From around 1994 to 2001, he was widely expected to become the leader of the country after his father.

In the late 90s, he was appointed to a senior position in the Ministry of Public Security. According to Gomi, he claimed his father outrightly refused to discuss the succession of power for many years because it indicated his own death.

But all this changed after he was arrested at Narita airport in Tokyo in May 2001 after it emerged he was travelling to the country on a forged Dominican Republic passport using a Chinese alias of Pang Xiong. At the time he told those questioning him that he had simply travelled to Japan to visit Disneyland. The highly-publicised incident caused Kim Jong-il to cancel a planned visit to China out of embarrassment.

North Korea Prison Camps Show all 7 1 /7 North Korea Prison Camps North Korea Prison Camps An overview of Camp 25 Amnesty International/DigitalGlobe North Korea Prison Camps The administration area of Camp 15 Amnesty International/DigitalGlobe North Korea Prison Camps A water treatment system in Camp 25 Amnesty International/DigitalGlobe North Korea Prison Camps Crop fields and, inset, prisoners in Camp 25 Amnesty International/DigitalGlobe North Korea Prison Camps The reported crematorium in Camp 25 Amnesty International/DigitalGlobe North Korea Prison Camps A possible mine Amnesty International/DigitalGlobe North Korea Prison Camps A walled compound in Camp 15 Amnesty International/DigitalGlobe

But according to Japanese magazine Shūkan Shinchō, he made several under the radar clandestine visits to Japan prior to the saga. A book about the Kim family called Under the Loving Care of the Fatherly Leader reported that he became "a familiar figure" at a bathhouse in Yoshiwara which is one of Tokyo's red light districts in the late 1990s.

He survived an assassination attempt

Back in 2011, Mr Kim survived an assassination attempt in Macau. This was around the same time as the death of his father. Pyongyang-watchers have claimed Kim Jong-Un was attempting to get rid of his half-brother to bolster his own claim to the leadership of North Korea.

He went into hiding

According to The Telegraph, North Korean analysts think he had good reason to go into hiding after the purge of his uncle and dozens of his closest allies in North Korea's business and diplomatic areas.

Mr Kim is believed to have been close to his deceased uncle and Mr Jang is thought to have passed funds to him via business contacts and the North Korean embassy in Malaysia.

He was critical of his half brother

A Japanese journalist and author Gomi claimed in 2011 Mr Kim told him his brother would fail.

"He's not comfortable that his younger brother is succeeding the power of Kim Jong Il," Gomi told CNN. "He (Mr Kim) sees his brother failing. He thinks he (Kim Jong-un) has a lack of experience, he's too young, and he didn't have enough time to be groomed. Those three reasons are why he thinks he'll fail."

He was previously predicted to have the safest chance of survival of all the Kim Jong-Il children

"I would say maybe this smart, overweight playboy from Macau has the highest chances of physical survival of all the Kim Jong Il children," Professor Andrei Lankov of Kookmin University told the outlet in 2012.