A new Iranian general has stepped out of the shadows to lead the country's expeditionary Quds Force, becoming responsible for Tehran's proxies across the Middle East as the Islamic Republic threatens the US with "harsh revenge" for killing its previous head Qassem Soleimani.
The Quds Force is part of the 125,000-strong Revolutionary Guard, a paramilitary organisation that answers only to Iran's Supreme Leader Ayatollah Ali Khamenei.
The Guard oversees Iran's ballistic missile programme, has its naval forces shadow the US Navy in the Persian Gulf, and includes an all-volunteer Basij force.
Like his predecessor, a young Esmail Ghaani faced the carnage of Iran's eight-year war with Iraq in the 1980s and later joined the newly-founded Quds, or Jerusalem, Force.
While much still remains unknown about Ghaani, 62, Western sanctions suggest he has long been in a position of power in the organisation.
One of his first duties is likely to be overseeing whatever revenge Iran intends to seek for the US air strike early on Friday that killed his friend Soleimani.
According to Iran's state-run IRNA news agency, Ghaani once said of his relationship with Soleimani: "We are children of war. We are comrades on the battlefield and we have become friends in battle."
The Guard has seen its influence grow ever-stronger both militarily and politically in recent decades. Iran's conventional military was decimated by the execution of its old officer class during the 1979 Islamic Revolution and later by sanctions.
A key driver of that influence comes from the elite Quds Force, which works across the region with allied groups to offer an asymmetrical threat to counter the advanced weaponry wielded by the US and its regional allies.
Those partners include Iraqi militiamen, Lebanon's Hezbollah and Yemen's Houthi rebels.
In announcing Ghaani as Soleimani's replacement, Ayatollah Ali Khamenei called the new leader "one of the most prominent commanders" in service to Iran.
Soleimani had long been the face of the Quds Force. His fame surged after American officials began blaming him for deadly roadside bombs targeting US troops in Iraq.
But while Soleimani's exploits in Iraq and Syria were well documented, Ghaani remained much more in the shadows of the organisation.
He has only occasionally come up in the Western or even Iranian media. But his personal story broadly mirrors that of Soleimani.
Born on August 8, 1957 in the north-eastern Iranian city of Mashhad, Ghaani grew up during the last decade of monarchy.
He joined the Guard a year after the 1979 revolution. Like Soleimani, he first deployed to put down the Kurdish uprising in Iran that followed the shah's downfall.
Iraq then invaded Iran, launching an eight-year war that would see one million people killed. Many of the dead were lightly armed members of the Guard, some of whom were young boys killed in human-wave assaults on Iraqi positions.
Volunteers "were seeing that all of them are being killed, but when we ordered them to go, would not hesitate", Ghaani later recounted.
He survived the war to join the Quds Force shortly after its creation. He worked with Soleimani, as well as leading counter-intelligence efforts at the Guard.
Western analysts believe while Soleimani focused on nations to Iran's west, Ghaani's remit was those to the east like Afghanistan and Pakistan.
In 2012, the US Treasury sanctioned Ghaani, describing him as having authority over "financial disbursements" to proxies affiliated with the Quds Force. The sanctions particularly tied Ghaani to an intercepted shipment of weapons seized at a port in 2010 in Lagos, Nigeria.
Also in 2012, Ghaani drew criticism from the US State Department after reportedly saying that "if the Islamic Republic was not present in Syria, the massacre of people would have happened on a much larger scale".
That comment came just after gunmen backing Syrian President Bashar Assad killed more than 100 people in Houla in the country's Homs province.
Then State Department spokeswoman Victoria Nuland said at the time: "Over the weekend we had the deputy head of the Quds Force saying publicly that they were proud of the role that they had played in training and assisting the Syrian forces – and look what this has wrought."
In January 2015, Ghaani indirectly said that Iran sends missiles and weapons to Palestinians to fight Israel.
"The US and Israel are too small to consider themselves in line with Iran's military power," Ghaani said at the time. "This power has now appeared alongside the oppressed people of Palestine and Gaza in the form of missiles and weapons."
Ghaani is now firmly in control of the Quds Force, while Iran's leaders plan to avenge Soleimani's death.
Whatever that plan is, Ghaani likely will be involved.
"If there were no Islamic Republic, the US would have burned the whole region," Ghaani once said.