The man, going only by the name "Aleksandr", told the Ukrainian Kyiv Post late last week that Putin's days are numbered.
He would be deposed "as soon as he becomes inconvenient for elites".
"It is very possible that he will lose his head in exchange for sanctions relief," the self-proclaimed resistance leader reportedly said. "In other words, the old man will become the fall guy and will be charged with everything that happened. Well, he certainly deserves that."
The existence of the NRA only came to light after it claimed responsibility for the car-bomb killing of 29-year-old pro-Putin propagandist Darya Dugina last month.
Dugina was the television personality daughter of Alexander Dugin, an extreme right-wing political philosopher. He has been dubbed "Putin's Rasputin" for his purported unofficial influence within the Kremlin's halls of power. He has also been widely accused of being the brains behind Russia's stalled invasion of Ukraine.
But not everything is as it seems.
Moscow's security services quickly concocted a convoluted story about the assassination being a Ukrainian plot. Meanwhile, others point out that "Putin's Rasputin" had himself suffered a potentially fatal fall from the President's graces.
News of the existence of the National Republican Army (NRA) emerged when former Kremlin parliamentarian Ilya Ponomarev alleged a member had approached him to publish their anti-Putin "manifesto".
He said Alexander Dugin had been the target of the Moscow car bomb but had escaped after a last-minute switch of cars.
Russia's Federal Security Service (FSB) has a different explanation for the attack.
Within 36 hours of the killing, it had accused a female Ukrainian secret service agent of escaping to Estonia with her young daughter and pet cat in a Mini Cooper.
Ukraine denies any involvement in the bombing.
Now the NRA says it has signed a "Declaration of Co-operation" with other anti-Putin groups to take the fight to the Kremlin.
Aleksandr, the group's leader, told Ukraine's Kyiv Post: "No Russian media has ever written about us – not even those in the Russian media who have already fled Russia; they're just all scared to death."
He does not expect an armed uprising to be successful, however.
"The situation has not yet matured. We believe that sporadic attacks against the authorities, their ideologues, and their media stooges could sow confusion among the Russian elites. If there is a split among the elites, they will start to bring down Putin's regime from within, from above. And we, the NRA, will do it from below."
It's exactly what the West wants to hear.
And that makes it suspicious.
"Very few observers believe the hitherto-unknown National Republican Army, which claimed responsibility for the killing, was to blame," says Australian National University strategic and defence studies analyst Matthew Sussex. "But if it were, then it points to the real possibility of organised domestic terrorism in Russia."
It's a long-established tactic of the Kremlin to sew together as many contradictory stories as necessary to smother an event with confusion. The idea is to leave people not believing anything – a position that only enhances an authoritarian's grip on power.
"Was it a pretext for Putin to ramp up his war in Ukraine? Could it have been a rogue anti-Putin faction?" @matthew_sussex writes for The Interpreter. "The truth is that we are unlikely to definitively discover who really killed Darya Dugina." https://t.co/TSNuum6lgL
It remains possible that Alexander Dugin was himself a target of the President's agents.
Unconfirmed reports of a growing cabal of dissatisfied Russian billionaires have so far proven unfounded. The idea makes sense – their wealth and influence are heavily affected by the ongoing, unsuccessful, invasion of Ukraine.
In March, Ukrainian intelligence alleged these elites were planning to overthrow the long-term leader of the Russian Federation. But little evidence of action has since emerged (except for an ongoing stream of deaths among high-profile Russian business executives – usually involving falling out of multi-storey buildings).
Alexander Dugin, however, is a unique case.
He may be Putin's inspiration for turning Moscow into "Third Rome". But he's also been particularly critical of the President's performance.
Not for invading Ukraine, but for not pursuing the war far more aggressively.
The Russian leader has not ordered open warfare. Instead, the invasion of Ukraine is a "special military operation" not requiring total mobilisation.
Alexander Dugin was fired from his position at Moscow State University in 2014 for criticising Putin's refusal to extend the invasion of Crimea into Donbas. And he reportedly authored an article published on a far-right website the same day as his daughter's death that called for "regime change" in Russia.
He stated the current leadership (meaning Putin) would not survive more than six more months.
"Let the old regime bury its dead. A new Russian time is coming. Relentlessly."
It would surprise no one if Alexander Dugin turned up dead.
"If the killing was carried out by the FSB itself, was it a rogue anti-Putin faction, or acting on Putin's orders to whip up flagging support for the war?" Sussex asks. "If the former, it points to a deep rift in Russia's elite. If the latter, Putin has cynically targeted Russia's ultra-right, which has criticised him for not being tough enough on Ukraine."
The Russian leader is fighting on three fronts, argues Sussex. He's fighting to seize Ukraine. He's struggling to dominate the Russian Federation. And he's staring down internal dissent.
"Putin has decimated Russia's conventional forces for surprisingly little gain in six months," Sussex says. "Along the way, he has blunted his own rhetoric about Russian power, demonstrated a callous disregard for human rights, and revealed his armed forces to be corrupt, poorly managed, and deficient in doctrine, discipline and capabilities."
It's not a good look.
And the aggressive nationalistic fervour he is attempting to whip up through state-controlled media and indoctrination of schoolchildren with the idea of a "greater Russia" may yet backfire.
"The car-bomb killing of Darya Dugina, daughter of Russia's neofascist philosopher Alexander Dugin, has prompted an outpouring of bile from the Russian extreme right," Sussex says.
"With it has come the first hint of domestic fragility in Russia since February's invasion, which saw 15,000 anti-war protesters arrested."
Putin's assassinations usually target political moderates. But they are always outspoken critics.
And that means Alexander Dugin fits the profile for the Kremlin's hit squads.
He is obsessed with control, Sussex says. And he has a massive propaganda and intelligence service to twist facts into unrecognisable shapes.
"That's a common vehicle for autocrats to deflect criticism, and has certainly worked for Putin. But unlikely though a Russian revolution from below may be, history is replete with examples – including the break-up of the Warsaw Pact and the USSR itself – where lies, repression and personalised power eventually revealed the Emperor's nakedness."