A reclusive figure with a love of poetry, Ahmed Abdi Godane became a feared jihadist, running assassination and bomb squads in Somalia.
He was assassinated in US air strikes in southern Somalia on 1 September.
He rose to the helm of the al-Qaeda-linked al-Shabab group in 2008 after his predecessor Aden Hashi Ayro was also killed in a previous US air strike in a remote village in southern Somalia.
Also known as Mukhtar Abu Zubair, Godane's ascent to power surprised some observers as he came from the breakaway northern region of Somaliland.
"His rise to power within al-Shabab is unparalleled and in many ways counterintuitive in the history of Somalia's political and military formations," Rashid Abdi, an East Africa analyst who specialises on al-Shabab, told the BBC.
"How did someone with no clan constituency in southern Somalia accumulate such powers and manage to command such following in a tribal country where clan loyalties and affiliation trump everything else?"
The answer probably lies in the fact that Godane was free of the clan rivalries which dominate southern Somalia, putting him in an ideal position to unite young Somalis under the banner of a hard-line Islamic ideology.
"He became Emir [an Arabic word for leader] of al-Shabab, a title that conferred him great spiritual clout. He became in effect the chief ideologue, custodian and interpreter of the 'pure' Salafi jihadi doctrine," Mr Abdi said.
The BBC Somali service's Mohammed Mohammed says Godane is fluent in Somali and Arabic, and has a reputation of being a fine orator and poet.
"When he spoke, he used poetry. One of his favourite poets was Mohammed Abdullah Hassan, dubbed the 'Mad Mullah' in the West but a big hero for Somalis because he fought against British colonial rule," he says.
Ahmed Abdi Godane at a glance:
- US put $7m (£4m) bounty on his head in 2012
- Pledged allegiance to al-Qaeda in 2009
- Became al-Shabab's top commander after US air strike killed his predecessor Aden Hashi Ayro in 2008
- Sentenced to death in absentia for 2008 attack in Somaliland's capital, Hargeisa
- Studied in Sudan and Pakistan, where he became radicalised
- Said to have fought in Afghanistan
- Reputed to be a good orator and poet
- Also known as Mukhtar Abu Zubair
- Killed in US air strike on 1 September 2014
Godane's exact date of birth is not known, but some reports say he was born in 1977 and had a difficult childhood - he is said to have spent time at an orphanage and his uncle was reportedly an alcoholic.
Nevertheless, he was bright and won scholarships to study Islam in Sudan and Pakistan, where he was heavily influenced by jihadi ideology in the 1990s.
From there, he is suspected to have crossed the border to Afghanistan to receive military training from al-Qaeda.
'Sword of Allah'
Godane first gained notoriety in 2008, when he was sentenced to death in absentia for the simultaneous bombing of the United Nations (UN) compound and Ethiopian embassy in Somaliland's capital, Hargeisa.
"He had been arrested prior to that, but released. The authorities did not know how dangerous he was," Mr Mohammed says.
"He was very focused on Islamic issues, and was said to have a good relationship with the top leadership of al-Qaeda. He featured in video tapes with al-Qaeda's leader Ayman al-Zawahiri, and all finances were said to have come through him."
Godane led al-Shabab into a formal alliance with al-Qaeda in 2009, changing its focus from a purely local jihad to a regional one.
In 2010, it killed 78 people watching the football World Cup in Uganda's capital, Kampala - the first bombing by al-Shabab outside Somalia.
Last year, at least 67 people were killed when al-Shabab fighters took control of the upmarket Westgate shopping centre in Kenya's capital, Nairobi, for four days.
"I have been sent ahead of the hour with the sword so that Allah will be worshipped alone without partners," Godane said, in a video praising the Westgate attack.
Mr Abdi says Godane proved to be ruthless within al-Shabab as well, ordering his "Amniyat" assassination squad to kill his critics - including US jihadi Omar Hammami, known as al-Amriki, and his one-time mentor and friend Ibrahim al-Afghani.
Godane carried out the purge last year after the disgruntled al-Shabab members wrote to al-Qaeda leader Ayman al-Zawahiri, accusing him of being autocratic.
"[Godane] takes decisions in a secret fashion without legitimate known reasons," they wrote.
The purge helped him strengthen his grip over al-Shabab, but it meant that he had also created many enemies in jihadi ranks.
Some of them may have turned into spies for the US, opening the way for the air strike which targeted his convoy in the Lower Shabelle region on 1 September.
The US had put a $7m (£4m) bounty on his head in 2012, giving his enemies further incentive to collaborate with the US in efforts to hunt him down.
Somalia analyst Abdi Aynte said it was difficult to imagine al-Shabab remaining cohesive without his leadership.
"The death of Ahmed Godane could deal a major blow to al-Shabab and could be the beginning of the end," he said on his Twitter account.
"The irony is that Godane killed the would-be obvious successor, Ibrahim al-Afghani, in a major internal rift last year," he added.