Kim Jong Il's heir — his third son Kim Jong Un — has risen to power swiftly in North Korea since being made a four-star general one year ago. But he is even more of an enigma than his late father.

Kim Jong Un is believed to be around 28 years old. His birth date, mother and marital status are not known. He is believed to speak several languages — including English and German — and is said to have been educated in Switzerland, and at the Kim Il Sung University in North Korea.

Kim Jong Un is believed to be skillful in using computers and other forms of technology. He is also described by a longtime family chef, in a memoir, as competitive and ruthless.

The elder Kim presented Jong Un as his successor a year ago, appointing him to top government posts. Over the past year, Kim Jong Un regularly accompanied his father on trips around the country. And he steadily built his political clout by reportedly becoming involved in domestic and foreign policy, and securing a position in the ruling Workers' Party.

Kim Jong Un was presented to the world last year at a massive military parade marking the 65th anniversary of the ruling Workers' Party, saluting troops by his father's side in an appearance captured live by international media.

Since his father's death on December 17, North Korean official media have hailed the younger Kim's leadership credentials, announcing that he had been appointed to the top post in the ruling communist party.

Other official media reports have referred to Mr. Kim as the “supreme leader of the revolutionary armed forces,” as well as the “supreme commander, ” a title that had also been used by his late father.