North Korea's reported nuclear test is not the first time Kim Jong-il has provoked the world and dismayed even his closest allies.
Since inheriting power in 1994, Kim has solidified his international reputation as an unpredictable leader whose intransigence has deepened North Korea's isolation.
Abroad, many consider the pudgy, bouffant-haired Kim a ruthless dictator who seeks atomic weapons while starving his people. But at home, the state-run media hails the "Dear Leader" as a prodigious general, an ace film director and the "Lodestar of the 21st Century."
Kim's latest nuclear standoff with the world stretches back to 2002 when Washington accused North Korea of developing a secret nuclear weapons program in violation of an earlier agreement. That year, US President George W. Bush branded the communist country part of an "axis of evil," along with Iran and Iraq.
Kim, 64, has since taken North Korea on an increasingly confrontational path, withdrawing from the Nuclear Nonproliferation Treaty, and culminating in yesterday's claim of nuclear weapons test.
In July, North Korea launched seven missiles into the Sea of Japan, ignoring international warnings and drawing condemnation from the UN Security Council.
The regime's report of a nuclear test came despite intense diplomatic appeals. China, the North's closest ally, quickly declared it was "resolutely opposed" to the move.
Nuclear weapons give North Korea an unparalleled deterrent from attack, something Kim has increasingly feared after watching the US invade Iraq and topple former Iraqi president Saddam Hussein.
The West's demonic image of Kim, however, goes back years before he took power. It is based in part on suspicions that he masterminded a 1983 terrorist bombing in Myanmar that killed 17 South Korean officials and the 1987 bombing of a South Korean airliner that killed all 115 people aboard.
Kim has ruled his country with a "military first" policy since the 1994 death of his father and North Korea's founder, Kim Il-sung. He controls the world's fifth-largest military, the 1.1 million-strong People's Army.
Some experts now believe North Korea may have separated plutonium enough to develop an arsenal consisting of four to 13 nuclear weapons, compared with estimates of one or two nuclear weapons in 2000.
Biographical insight on Kim is extremely sketchy. He rarely appears in public and his voice is seldom broadcast.