Mullah Haibatullah Akhundzada, named today as the Afghan Taliban's new leader, was a senior judge during the insurgent group's five-year rule over Afghanistan and a close confidant of its founder Mullah Omar.
Believed to be in his fifties, he hails from Afghanistan's southern province of Kandahar like both his former boss -- Mullah Akhtar Mansour, who was killed in a US drone strike on Saturday -- and Omar, who died in 2013.
Akhundzada went on to become the group's "chief justice" after a US-led invasion toppled the Taliban government in 2001.
He was one of Mansour's deputies alongside Sirajuddin Haqqani, leader of the feared Haqqani network based out of eastern Afghanistan.
Several senior Taliban sources have said Mansour bequeathed Akhunzada the leadership in his will, though some observers have argued in the past that hereditary succession is against the Taliban's ideology.
Akhundzada is not known for his prowess on the battlefield, having preferred a life of religious and legal study.
He is said to have issued many of the rulings on how Muslims should comply with the Taliban's extreme interpretation of Islam, and adjudicated internal disputes.
"He is a religious scholar who was close to Mullah Omar, a close confidant and an adviser on religious issues who wrote fatwas, and was on the council of Ulema (Muslim scholars)," said Thomas Ruttig, a former diplomat and co-director of the Kabul-based Afghan Analysts Network.
A senior Taliban source familiar with proceedings at the Shura (council) which appointed Akhundzada said he was a unanimous choice, adding the group's rank and file looked to him as a "spiritual leader" who had taught thousands of students in both Pakistan and Afghanistan over 25 years.
According to Rahimullah Yousafzai, considered the region's foremost expert on the Taliban, Akhundzada was in Pakistan during the 1979-89 Soviet occupation of Afghanistan -- unlike Omar and Mansour, who earned reputations as fighters as part of the US-backed mujahideen.
But he returned to his homeland in time to attend the meeting in the town of Spin Boldak in Kandahar in 1994 at which Omar declared the birth of the Taliban movement, according to the senior militant source.
