North Korean leader Kim Jong-un visited a mausoleum in Pyongyang on Thursday to pay respects to his father, who died four years ago. The abrupt death of Kim Jong-il on Dec. 17, 2011, put the young heir-apparent on the throne in the second dynastic succession of power in the country.

Over his four years in power, the junior Kim has ruled the communist country in a way little different from his father and grandfather, North Korea’s founder Kim Il-sung, as he relied on the legacy of the Kim dynasty to strengthen his grip on the country.

“Reign of terror” is the most frequently used term to describe the rule of Kim Jong-un. He inherited the vicious purges of military and government elite, totalitarian control of society and human rights violations that have been part of the Kim family’s harsh rule, reminiscent of the Soviet and Nazi regimes.

But the young leader has turned out to be more vicious and merciless than his forefathers. Kim resorts to fear among the military, Workers’ Party and government elite all the more because he was given power at an earlier-than-expected day and while he was still young -- in his 20s.

Indeed, the South Korean intelligence service believes that, since assuming power, Kim ordered the execution of about 100 party and military officials. The victims included his uncle Jang Song-thaek, whose arrest, interrogation and trial were adroitly made public through state media; former defense chief Hyon Yong-chol, who is believed to have been killed with an anti-aircraft gun; and Vice Marshal and General Chief of Staff Ri Yong-ho. All were close associates of his father, and before the brutal purge, members of his own inner circle.

While building up his image as a stern leader who allows no signs of disloyalty, Kim is trying to instill the image of a caring and friendly leader among the general public.

It is common for the state media to release photos of young rank-and-file soldiers and workers linking arms with the Dear Leader. Kim, who studied in France and Switzerland when he was young, also seeks some degree of openness for the North Korean economy, which, according to outside experts, is improving.

Under Kim’s four-year rule, North Korea’s foreign policy has not changed much. As in the past, unpredictability is another feature of the Kim Jong-un regime. The most recent example is the last-minute cancellation of a performance by the North’s Moranbong propaganda girl band in Beijing, which raised speculations about its ties with the Chinese leadership.

The outside world’s biggest concern is about Kim’s aggressive pursuit of long-range missiles and weapons of mass destruction, including nuclear weapons. Kim, hoping to show off his leadership and capability, is becoming personally involved in the development of submarine-launched ballistic missiles and other sophisticated weapons. He even implied recently that the North had hydrogen bombs.

The North’s relations with South Korea and the U.S. also remain frosty, and the prospects for resuming the six-party talks on the North’s nuclear program are dim. Kim has yet to invite a foreign head of state or travel outside the country.

All these things show that, four years after taking power, Kim is not trying to make any significant change of course for the country, which keeps the outside world wondering what kind of leader he will shape up to be. This is not mere curiosity, since the future of him and his country will have an immense impact on the Korean Peninsula and beyond.