Al-Qaeda number two Ayman al-Zawahiri, the Egyptian surgeon considered the real mastermind of the global terror franchise, is now set to succeed Osama bin Laden as the world's most wanted man.
Like his Saudi-born co-conspirator, Zawahiri has been hiding ever since the United States declared its war on terror after the September 11, 2001 attacks.
Unlike his late comrade, who President Barack Obama said was killed by U.S. forces in Pakistan, Zawahiri is presumed still at large with organisational skills, cunning and intelligence said to eclipse that of bin Laden.
Reportedly last seen in October 2001 in eastern Afghanistan, close to the Pakistan border, he has released multiple videos from his hiding, calling for war on the West.
While bin Laden was seen as al-Qaeda's inspiration, his deputy is believed to be the real brains that steered operations, including the September 11 attacks, and as a result arguably even more dangerous.
The former eye surgeon's position as bin Laden's main strategist and mentor earned the 59-year-old a $25 million bounty on his head.
The U.S. Federal Bureau of Investigation's list of most wanted terrorists said he was also bin Laden's personal doctor. As bin Laden withdrew from the public eye after 2004, it was often up to Zawahiri to motivate the group's followers with a series of hectoring video appearances, jabbing his finger and staring from behind heavy-rimmed glasses. Zawahiri met bin Laden when thousands of Islamist fighters from around the world flooded into Afghanistan during the 1980s jihad against Soviet forces.