MOSCOW (AP) -- Igor Ivanovich Sechin, the CEO of Russian state-owned oil company Rosneft and a loyal aide to Russian President Vladimir Putin for more than 20 years, was the driving force behind Monday's deal to take over rival TNK-BP.

Here's a look at the man who in less than a decade has transformed the once-obscure, state-controlled Russian company into the world's largest publicly traded oil company, in terms of production.

Putin's shadow
Like Putin, Sechin is a native of the city of Leningrad, now called St. Petersburg, and is widely believed to share his background in the Soviet intelligence services. In the 1980s, Sechin worked as a Portuguese translator in Mozambique and Angola. He went to work for Putin at Leningrad City Hall in 1991 and followed him to Moscow in 1996, where they have remained inseparable ever since.

Sechin's influence is captured by a popular joke said to be based on real events back when Sechin worked at the Kremlin: Putin calls the Kremlin switchboard and asks to be put through to Igor Ivanovich, without specifying the last name. When the operator asks whether he wants to speak with Igor Ivanovich Sechin or Igor Ivanovich Shuvalov -- another of Putin's top aides -- Putin replies, "the real one." The operator transfers him to Sechin.

Sechin is now widely known as "The Real One" or "Putin's Shadow."

Russian President Vladimir Putin listens to Igor Sechin, Rosneft CEO, right, at the Novo-Ogaryovo residence on Monday, Oct. 22, 2012. (AP Photo/RIA Novosti, Alexei Nikolsky, Presidential Press Service)

Yukos
As deputy head of Putin's presidential administration from 2000 to 2008, Sechin was behind the dismantling of Russia's largest oil company, Yukos, after the arrest in 2003 of its billionaire owner, Mikhail Khodorkovsky, on charges of tax evasion.

Yukos' most lucrative assets ended up in the hands of Rosneft.

First, Yukos' most valuable part, the Yuganskneftegaz unit -- worth up to $20 billion -- was sold by an official bankruptcy receiver in December 2004 for about $9.3 billion to an obscure company with capital of just 10,000 rubles (about $300). Days later, Rosneft bought the company for 100 rubles, becoming Russia's second-largest oil company at the time at a bargain price. A former official at the state property agency says Sechin was behind the scheme.

Khodorkovsky, who remains in prison, has accused Sechin of driving both of the criminal cases brought against him.

Rosneft
Rosneft has been state-owned since 1993, when it was created with the assets belonging to the Soviet Oil and Gas Ministry. Some of its assets have since then been privatized and spun off. Rosneft is currently 75% state-owned.

Shortly before he dismantled Yukos, Sechin was appointed by the Russian government to become chairman of Rosneft's board in 2004. During his time as chairman he still held several government posts.

In 2011, when he was Putin's deputy in charge of energy, he was forced to give up his role at Rosneft in compliance with then-President Dmitry Medvedev's order that government ministers could no longer serve on the boards of state-owned companies.

But Sechin managed to keep his grip on the company. He arranged several key deals to help the company gain the technology and expertise needed for an ambitious foray into the Arctic. These included multibillion-dollar alliances with ExxonMobil (NYSE: XOM), Norway's Statoil (NYSE: STO) and Italy's Eni (NYSE: E).

Sechin's public appearances also left little doubt that he remained in charge. Whenever Rosneft's CEO during the period, Eduard Khudainatov, was asked a question, Sechin would take the floor and answer it if he was present.

In May, with Putin back as president for a third term, Sechin gave up his government post as Putin's energy deputy and was appointed chief executive of the company.

Latin America
In recent years, Sechin has overseen Russian energy projects in Latin America, touring the continent and making friends with Venezuelan President Hugo Chavez. Energy analysts say that most of the Russian projects in Latin America are economically unsound but are designed to maintain political support from regimes, such as Chavez's, which are friendly toward the Kremlin.

TNK-BP
In January 2011, Sechin and BP (NYSE: BP) CEO Bob Dudley agreed -- with Putin's blessing -- to strike a deal in which the companies would swap shares and cooperate in the search for oil in the Arctic. But BP already had a joint venture in Russia, called TNK- BP, and the four Russian billionaires who control the other half of TNK-BP sued BP to block the deal.

BP became fed up with the four tycoons' stonewalling and said it would sell its stake in the joint venture.

In the end, Rosneft bought not only BP's half -- for $17.1 billion in cash and a 12.84% stake in Rosneft -- but the billionaires' half as well, for $28 billion.

The deal will put Sechin at the head of the world's largest publicly traded producer of oil and gas in terms of output, with 4.6 million barrels per day compared with ExxonMobil's 4.2 million barrels.