Billionaire Aristotelis Mistakidis, the so-called “King of Copper” and head of the Swiss-based Glencore’s copper division, is going to retire as the company has come under a growing number of investigations and legal problems, ending his reign that began as a secretive commodity trader.

Mistakidis, 56, had built the company’s reputation as a giant in the copper business but fell victim to a shakeup and will be replaced by the head of copper marketing and fellow Greek, Nico Paraskevas, media reports said.

With a reported net worth of $2 billion, Mistakidis is a native of Greece, a graduate of Louisiana State University and a citizen of the United Kingdom. He’s known as Telis and owns a 3.2 percent stake in the company which was ordered by the US department of justice in July to hand over documents about its business in the Congo, Venezuela and Nigeria as part of a corruption probe.

Canadian regulators are also investigating accounting irregularities at copper mines where Mistakidis was a director, said the financial news agency Bloomberg. Paraskevas has spent 12 years with Glencore and helped lead the sale of Las Bambas copper mine in Peru.

The roiling at the company have rattled its worth with expectations for a $2.7 billion profit in the trading division, down from as much as $3.2 billion. In a Bloomberg News profile of Mistakidis in October, his current and former colleagues, clients and competitors described him as energetic, cheerful and charming, but a sharp and ruthless negotiator. He speaks five languages.

The move is an unusual setback for Mistakidis who rose to prominence on the back of his drive and skills, but saw the company under fire over its copper business in Congo. Last year he resigned from the board of Katanga Mining, the unit through which Glencore holds its Congolese copper assets, after an internal review found “material weaknesses” in its accounting.

Katanga overstated its copper output and inventories, and in some cases senior management and executive directors were responsible for “overriding the company’s control processes,” the review found, said Bloomberg, leading Katanga to be investigated by the Ontario Securities Commission over whether it misled investors.

The scrutiny has put a spotlight on how Mistakidis came to be so successful and led him to be the talk of the close-knit and powerful industry and ending hopes he would become the Chief Executive to succeed Ivan Glasenberg, who has run the company for 16 years.

“He’s one of the smartest guys in the market,” David Lilley, Managing Director of Drakewood Capital Management, who started his career working with Mistakidis at Cargill in the 1980s told the news agency. “He’s very insightful and incredibly well informed. He also has an amazing ability to buy low and sell high.”

A native of Thessaloniki, Mistakidis spent his early childhood in Rome, where his father worked as a marine biologist for the United Nations. He moved to England to attend a boarding school in Essex, before studying at the London School of Economics, Bloomberg said in a profile.

He was described as a demanding boss obsessed with the secrecy of Glencore’s positions and someone who inspired instead of demanded loyalty, staying close to his traders by having lunch with them daily when London Metal Exchange had finished the morning session.

“He has no time for bootlickers, laziness, stupidity. He would always try to rattle people to get a better deal, or to get more out of you, often confusing people on purpose,” said Sebastien Le Page, a senior copper trader at Glencore until 2015. “We worked hard, but had so much fun all together. Telis made me laugh to tears so many times.”

In 2014, he spent $70 million to buy a luxury flat in London’s Belgravia. He’s still a workaholic with an endless appetite for information, whose first passion is for markets and the political and economic shifts that move them, the profile said.

His drive showed when Glencore expanded in 2013 and took over Xstrata, a London-listed miner that had a reputation for executive inefficiency and a weak worth ethic he couldn’t abide

He squeezed the mines for profit, cutting more than 1,000 jobs from its Australian copper mines. Glencore’s copper assets made more money in 2017, when copper prices averaged $6,200 a ton, than in 2014, when the average was $6,800, but then the light was put on the operation.

Glencore’s links with Dan Gertler, an Israeli who is under U.S. sanctions for allegedly corrupt deals in Congo, have long been a cause of worry and the internal review led Mistakidis to then stop heading the copper assets division.