He is arguably the second most powerful man in Russia, yet his name is seldom – if ever – mentioned.
His influence is felt in every corner of the Kremlin, yet he holds no official office.
He is Russian strongman Vladimir Putin’s most trusted adviser, yet he has barely any formal education.
He is Sergei Vasiliy Popov and he has been compared to the infamous Grigori Rasputin whose debauchery helped bring down Czar Nicholas the Second.
Like Rasputin, Popov is a hard-drinking, foul-mouthed, womanising, Russian Orthodox zealot.
While behind his back they might call him “Ras-Putin and the “modern day Mad Monk,” it is Popov’s sinister hold over the the President that has Kremlin insiders – and western leaders – deeply worried.
Analysts say it was shortly after a “man’s retreat” – code for 5 days of hard drinking and lechery – with Popov that Vladimir Putin significantly toughened his existing KGB hardliner image.
He began appearing in ever increasingly macho guises; shirtless, frequently armed, or in overtly militaristic or “action man” poses.
But analysts say this is the least concerning manifestation of Popov’s behind the scenes power play.
They note that Russia’s military posturing has become bolder and more reckless as – in the words of one White House insider; “Putin seeks to be the hellraiser his mad monk mate expects him to be.”
“It’s Dumb and Dumber on the world stage,” the White House official says.
“It would be pathetic if it wasn’t so damned dangerous.”
For his part, Popov gives no interviews and holds no official position in the Russian government.
He is said to live rent-free in a lavish refurbished office-turned-apartment in the notorious Lubyanka building which once housed the KGB and an unknown number of the ruthless secret police’s unwilling guests.
In a telling sign of his influence, Popov is reported to hold almost daily meetings there with a doting President Putin; oftentimes with the controversial mystic propped up in bed in his pyjamas as the Russian leader solicits his advice or “spiritual counselling” on affairs of state.
It is, the White House insider, laments; “an unholy alliance.”