Kim Jong Il, supreme leader of North Korea, died on Saturday at the age of 69 after suffering a fatal heart attack. The Great Successor of North Korea's Dear Leader will be his son, Kim Jong Un.

But who exactly is Kim Jong Un? There is little information known about Kim Jong Il's youngest son. His age is even a glaring question mark (he is either 27 or 28-years-old).

Here are seven things to know about the man who will take charge of North Korea and have the power to change the course of the world.

He attended school in Switzerland.

Kim Jong Un reportedly attended school in Bern, a suburb in Switzerland, under a pseudonym. Indeed, its presence is wrapped in an incredible mystery, said Julie Zaugg, a journalist with the Swiss magazine L'Hebdo. At the International School of Gümlingen, located a few meters from the North Korean Embassy, ??the adolescent was written under the pseudonym 'Pak Chol' and posed as the son of a chauffeur. An older student that he called 'Chol Wang,' accompanied him at all times. This provoked suspicion amongst his classmates.

He was obsessed with basketball.

Students at Bern's German-speaking Liebefeld-Steinholzli School described Kim Jong Un as unremarkable and obsessed with basketball. He proudly showed off photographs of himself standing with Toni Kukoc of the Chicago Bulls and Kobe Bryant of the Los Angeles Lakers. It is unclear where the pictures were taken. On at least one occasion, a car from the North Korean Embassy drove Pak Un to Paris to watch an NBA exhibition game, the source said.

He was shy with girls but a formidable competitor on the basketball court.A fiercely competitive player, said classmate Nikola Kovacevic. He was very explosive. He could make things happen. He was the playmaker.

He had an expansive collection of pricey Nike sneakers.

He also had a collection of Nike sneakers. We only dreamed about having such shoes. He was wearing them, recalled Kovacevic, who thinks each pair cost about $200.

He was mentored by Switzerland's former ambassador to North Korea.

Supposedly Kim Jong Un was groomed as a youngster by the former ambassador to North Korea in Switzerland, Ri Tcheul. He had come for Kim in a Limousine to Berne and rumors say it is split by a deep reverence on seeing him, said Ron Hochuli, a journalist for the Swiss Television. To me, he did not leave Switzerland by chance perhaps to support Kim Jong-un in his rise to power. Ri Tcheul was a real babysitter for all the siblings!

He disappeared in 2000.

Kim disappeared in 2000, when he should have entered into middle school. Apparently, at this time, he returned to Pyongyang, reports The Washington Post. Kim Jong Un had not been seen in public until he emerged as his father's heir-apparent last year. 

He possibly underwent plastic surgery to look more like his grandfather, Kim Il-Sung.

Reports surfaced in 2010 that Kim Jong Un might have went under the knife to look more like his grandfather, North Korea's former Dear Leader, Kim Il-Sung. The Telegraph reported that there was a striking difference between the younger Kim Jong Un and the one who appeared last year. The first official photographs of Kim Jong Il's youngest son revealed an unmistakable resemblance to his grandfather. South Korean newspapers speculated that this new look was part of a concerted effort to raise the hitherto unknown prospective leader's standing with the public, a sort of 'reincarnation of North Korea's late founder.'

His policies are unknown; and the world waits with bated breath.

Kim Jong-un is completely untried, indeed he has been plunged into this, with only two years to prepare. So far we have no reason to think he has the abilities to exercise power in his own right, said Aidan Foster-Carter, a British expert on North Korea.

The military may look at this callow youth and say ok we can use him as a figurehead or it may go the other way and we get a full military regime, a ruling council. The party had rather atrophied under Kim Jong-il until it came together to back Kim Jong-un for the leadership.

There may be some rivalries there that would help him. So it's a question of whether he will go with the grain or decide to be bold and open up to the international community, Foster-Carter added.