In the eyes of some, he is the Islamic world's most powerful gun-for-hire, a well-connected ex-general with thousands of battle-hardened Syrian mercenaries at his command. A close confidant of Turkey's president Recep Tayyip Erdogan, Adnan Tanriverdi claims expertise in all the dark arts of warfare, from sabotage and counter-insurgency to assassinations.
But as with many prominent soldiers of fortune, it can be hard separating the man from the myth. Is he, as critics say, Mr Erdogan's private henchman, running secret Islamist armies in Libya and Syria? Or is he, as he himself claims, just a respectable patriot who has been smeared by the president's enemies?
"We haven't sent any mercenaries or other personnel to Syria or Libya," he insisted to The Telegraph last week, after he was accused by the US government of dispatching thousands of Syrian fighters to Libya. "I would like to highlight again that our firm is not a mercenary organisation. It doesn't have any connections with terrorist organisations or groups."
Generals at the Pentagon's Africa Command beg to differ. In a report to the US government earlier this month, they said Sadat was supervising around 5,000 Syrian mercenaries - including "extremists with previous terrorist links" - in Libya. The hired guns were said to fighting for the Government of National Accord, the side Ankara has backed in Libya's civil war.
The report said the mercenaries, allegedly paid and mentored by several dozen Sadat trainers, had helped the GNA retake territory from Khalifa Heftar, the Gaddafi-era strongman backed by Turkey’s rivals, the UAE and Egypt. But it claimed that many of the fighters had also run amok. "There were increasing reports of theft, sexual assault and misconduct by these mercenaries, which is likely to further degrade the security situation," it said.
The US allegations have fuelled the growing sense of intrigue around Sadat Group in Turkey, which Mr Erdogan's opponents say acts like a private presidential army. They draw comparisons with Russia's Wagner Group, which does foreign military operations for President Vladimir Putin, including fighting for General Heftar's forces in Libya.
The claims come as Mr Erdogan seeks to expand Turkey's military influence abroad, restoring its Ottoman-era glory as the Islamic world's foremost power. He is currently in a stand-off with European leaders over his decision to resume gas exploration in contested waters around Greece and Cyprus, parts of the Mediterranean that Turkey regards as its backyard.
A former special forces commander, Mr Tanriverdi was among a group of officers allegedly forced out of the military in the late 1990s because they shared Mr Erdogan's Islamist leanings. He set up Sadat Group with other ex-colleagues in 2012, although unlike other most soldiers of fortune, who simply work for the highest bidder, he has an ideology: to train Muslim nation's armies to the point where they are no longer reliant on Western help.
Or, as his website, which has flashy videos of elite forces in training, puts it: "The aim of Sadat Defense is to help the Islamic World take the place where it merits among Super Powers."
Sadat, he claims, operates like any other modern private military firm, offering governments training in soldiering and counter-insurgency. However, like Wagner Group, its activities are swathed in secrecy, with Mr Tanriverdi declining to say publicly in which countries it has set up operations.
That has not stopped Turkey's opposition politicians, who have a tense relationship with Mr Erdogan, detecting Sadat's hand in all manner of skulduggery. As well as allegedly training Islamist fighters in Syria and Libya, the group is accused of giving the president behind-the-scenes help in defeating the attempted military coup against him in 2016. Sadat officers, it is claimed, were involved in some of the vicious street fighting that took place in Istanbul as the coup was quelled.
Those suspicions stemmed partly from the fact that shortly after the coup, Mr Erdogan made Mr Tanriverdi his chief military advisor. He resigned earlier this year, after a controversial speech in which he said Sadat was paving the way for the return of the Mahdi, a Messianic figure in Islam.
Two years ago, Meral Akşener, a former Turkish interior minister and secular opposition politician, alleged that Sadat had also been running training camps for pro-government militias near Turkey's Black Sea coast. Their job, she claimed, was to stir up trouble if elections did not favour President Erdogan's ruling AKP party.
Mr Tanriverdi denies such claims, insisting to the Telegraph that his firm had less than a dozen advisors, none of whom were ever deployed in direct combat. "Do you think a firm that has about ten staff can have a role in suppressing a coup plot?" he claimed.
He also bristled when asked if Sadat formed the president's private army, suggesting it was a notion that only a British newspaper might believe. "Turkey is a democratic republic, its head of state is chosen by popular vote," he asked. "Since we don't have kings or queens, dominance of a family or hereditary rulership, you might be having hard times to understand."
Professor Howard Eissenstat, an expert on Turkey at New York's St Lawrence University, said Turkey's opposition had perhaps over-exaggerated Sadat's importance, taking at face value the grandiose vision spelt out on its website.
But he added: "I don't think there is any question that Sadat has worked closely with the Turkish government in Syria and Libya, and they are very explicit about this idea of projecting Turkish power to the Muslim world. We just have to be wary about assuming that they are as important as they present themselves to be."
That would appear to be a view shared by Mr Tanriverdi, who claims his only mission to Libya was in 2013, when his firm negotiated for a bid to build a military pentathlon facility for the Libyan army.
“Because of the unrest in Libya, the negotiations stopped,” he said.
He insisted, though, that there would soon be many other Turkish firms like his touting for military business. "Turkey needs tens of, maybe hundreds of, firms like Sadat," he added. "This is for the security, prosperity and survival of Islamic nations."