In a story that has become part of jihadi lore, Ayman al-Zawahri, the man succeeding Osama bin Laden as leader of al-Qaida, once ordered his followers to dig a huge hole in the east of Afghanistan.
It was near the end of the Soviet occupation of the country in the late 1980s, and al-Zawahri's followers were curious about the pit's purpose, recalled Noman Benotman, a former commander of the Libyan Islamic Fighting Group (LIFG).
"(Al-Zawahri) said it is just a swimming pool for the people to enjoy themselves in the summer," the former bin Laden associate told msnbc.com.
"But it ended up being a prison when they finished it," said Benotman, who now eschews violence and is a senior analyst at British counter-extremist think tank Quilliam.
The wartime jail was meant to impress on the men fighting with al-Zawahri how far he would go to enforce his will and establish discipline, Benotman said.
Osama bin Laden's longtime deputy has long brought discipline, ideological fire and tactical and organizational cunning to al-Qaida, which has found itself increasingly decentralized and prone to internal disputes following its expulsion from Afghanistan after its invasion by U.S. forces in 2001.
But while al-Zawahri, who turns 60 in a few days, is said to have been behind the use of suicide bombings and the independent militant cells that have become the network's trademarks, he is also thought to be a controlling micromanager who lacks bin Laden's charisma.
"When you join al-Qaida you don't swear an oath of allegiance to al-Qaida," journalist and author Peter Bergen told NBC News after bin Laden's death in May. "You swear a personal oath of allegiance to Osama bin Laden."
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"He's (al-Zawahri) not well-liked or well-regarded, even by people in his own Egyptian sort of jihad group," he said. "He's regarded as a divisive figure."
According to Bergen, many people who knew bin Laden said they loved him even if they disagreed with his methods.
"No one describes feelings of love for Ayman al-Zawahri," Bergen added.
Al-Zawahri was one of the biggest proponents of transforming al-Qaida from a local guerilla resistance group in Afghanistan to a terror organization with a global reach, according to Charlene Gubash, NBC News Producer in Cairo.
His appointment means al-Qaida will continue trying to attack the United States and European countries involved in Afghanistan and Iraq, with the goal of forcing the West from Arab lands, she said.
Al-Zawahri has tried to portray the so-called "Arab Spring" uprisings as a collective desire by people in the Mideast to replace their leaders with Islamic governments, Gubash said.
His personality and leadership style was forged over many years fighting against Western and Israeli interests.
He is the son of an upper middle-class Egyptian family of doctors and scholars. His father was a pharmacology professor at Cairo University's medical school and his grandfather was the grand imam of Al-Azhar University, a premier center of religious study.
At the age of 15, he founded his first underground cell of high school students to oppose the Egyptian government. He continued his militant activities while earning his medical degree, later merging his cell with other militants to form Islamic Jihad.
Al-Zawahri served three years in an Egyptian prison before heading to Afghanistan in 1984 to fight the Soviets, where he linked up with bin Laden. Al-Zawahri later followed bin Laden to Sudan and then back to Afghanistan, where they found a haven under the radical Taliban regime.Interactive: Al-Qaida timeline (on this page)
Soon after came the 1998 bombings of the U.S. embassies in Africa, followed by the 2000 suicide bombing of the USS Cole off the coast of Yemen, an attack al-Zawahri is believed to have helped organize.
In a 2001 treatise, he set down the long-term strategy for the jihadi movement — to inflict "as many casualties as possible" on the Americans.
"Pursuing the Americans and Jews is not an impossible task," he wrote. "Killing them is not impossible, whether by a bullet, a knife stab, a bomb or a strike with an iron bar."
Hatred for Americans
Al-Zawahri's hatred for Americans has also become deeply personal: His wife and at least two of their six children were killed in a U.S. airstrike following the 2001 U.S. invasion of Afghanistan after the September 11 attacks.
While he has the passion and track record, al-Zawahri also has a reputation as a stubborn and contentious individual who is not universally popular among jihadis, Former CIA operations officer John J. Lebeau told Reuters.
"He will tenuously preside over an organization that has to an important extent mutated into loose networks of quasi-autonomous units which make their own decisions and plan and conduct their own operations," he said.
But Benotman warns that al-Zawahri's abrasive personality doesn't necessarily mean he will fail.
"I don’t think it’s going to be easy for al-Qaida ... to adapt to this new leadership," he said. "But we can't forget (al-Zawahri's) skills.
"He is more intellectual than bin Laden. He's very smart," Benotman said, adding: "He's an ... exceptional militant leader, full of experience."
The Associated Press, Reuters and msnbc.com staff contributed to this report.