Abu Ibrahim al-Quraishi, a religious scholar and former soldier in Iraqi leader Saddam Hussein’s army, led Islamic State from the shadows for a little over two years before he blew himself up during a raid by US forces on a house in northern Syria.
The 45-year-old Iraqi had been an important leader in Islamic State's precursor, the Islamic State of Iraq - an offshoot of al Qaeda - since soon after the US invasion that toppled Saddam in 2003.
Quraishi, was named the leader of Islamic State, a violent Sunni Muslim jihadist group, shortly after his predecessor Abu Bakr al-Baghdadi also blew himself up during a U.S. operation in 2019 in Syria.
Baghdadi had declared a medieval-style Islamic caliphate from a mosque in the Iraqi city of Mosul after his militants overran the city and then seized vast swathes of Iraq and Syria in 2014.
By contrast, Quraishi was a shadowy figure who led the group at a time when it was under intense military pressure from US-led, Iraqi and other forces after losing all the territory it had once controlled.
Quraishi had also gone by the names Abdullah Amir Mohammed Saeed al-Mawla and Hajji Abdullah Qardash.
US officials described Quraishi after his death as the "driving force" behind the 2014 genocide of minority Yazidis in northern Iraq, and said he oversaw a network of Islamic State branches from Africa to Afghanistan.
Quraishi was born in 1976 in Muhallabiya, a small town inhabited mostly by Iraq's Turkmen minority to the west of Mosul, the son of a preacher who led Muslim Friday prayers in a mosque in the nearby city.
Having read Islamic studies at university in Mosul he was specialised more in religious guidance and Islamic jurisprudence than in Islamic State's security and military doctrine, but gained experience through membership of jihadist groups, according to Iraqi security officials.
Once detained by US
In 2008 US forces captured Quraishi in Mosul and detained him in a US detention facility called Camp Bucca, according to research by Feras Kilani, a BBC correspondent who interviewed Quraishi and carried out an investigation into Islamic State's leadership after Baghdadi.
Camp Bucca was notorious for holding al-Qaeda and Islamic State of Iraq inmates who made important connections with each other while in the jail, including Baghdadi. Quraishi was released the following year.
Quraishi had joined the jihadist insurgency against the US occupation of Iraq between 2003 and 2004, according to Kilani, and eventually worked his way up the ranks of Islamic State.
At some point in the past, he had served in Saddam's army, Iraqi security officials say. Many insurgents took up arms against US troops after Washington's representative in Iraq ordered the disbanding of the Iraqi military and black-listed thousands of commanders associated with Saddam's Baath party.
Iraqi security officials said Quraishi fled across the border to Syria when the group was routed in 2017 and had since been hiding out in remote areas, moving around to avoid detection and trying to resuscitate Islamic State.
His nom-de-guerre, Quraishi, indicates that he is believed to trace his lineage from the Prophet Mohammed, giving him religious clout among fellow jihadists.