One major group refuses to submit: Right Sector.
This organization was formed during the 2013-2014 Euromaidan revolution from hardened protesters and far-right, fringe parties.
Analysts say Right Sector has thousands of members, including hundreds of armed men deployed alongside Ukrainian government troops.
Despite official claims to the contrary, fresh recruits continue to arrive and operate with regular troops.
“It’s generally understood the army controls Right Sector fighters,” says Vyacheslav Likhachev, an analyst of right-wing radicalism.
“Their every step is coordinated with Ukraine’s commanders.”
Ukraine’s Defense Ministry did not respond to a request for comment.
For now, Kiev benefits from these guerrilla units; they’re highly motivated and don’t qualify for state pensions.
Longer term, the government is playing with fire.
Right Sector’s existence undermines Kiev’s standing within Europe, and — if peace talks ever gain momentum — this group probably would reject any compromise and could push a volatile region deeper into conflict.
But with fighting picking up along the front here, just at the moment when many Ukrainians have been worrying that President Trump’s desire to reset relations with Russia will cast their country into the cold, there’s little likelihood that Kiev will move anytime soon against the Right Sector fighters.
They are admired for their fierce dedication, but belligerent statements and menacing demonstrations have sullied the group’s reputation.
Russian state media demonize the organization and exaggerate its importance, painting it as the military wing of a (fictional) fascist junta.
Moscow has freely exploited Ukraine’s troubled history with the extreme right.
Some Ukrainian nationalists fought against the Nazis during World War II, but others committed atrocities alongside the Germans.
The maverick organization does contain neo-Nazi elements. It also has fighters with no far-right sympathies.
All despise Ukraine’s corrupt officialdom.
‘Something big’s happening’
Volunteer units guard the little town of Marinka, living in squalid, abandoned cottages.
At a position overlooking separatist-held Donetsk, two foreigners stand out: an Italian neo-Nazi and a young Dutchman.
The two share a thirst for adventure and a total ignorance of the local language.
Giuseppe Donene’s T-shirt echoes a Nazi-era war flag, emblazoned with the word “Hatred.”
Despite his extreme ideology, he is disarmingly affable. What prompted him to enlist?
“This is Europe, my house. But governments don’t let us fight,” he says.
He complains that Europe is losing its identity to Muslims and African immigrants, and maintains that eastern Ukraine is the place to take a stand.
“Something big’s happening here. It’s worth fighting for.”
This 47-year-old married father of two has worked in private security in Angola, Iraq, Sudan and Syria.
Every few months, he takes leave to join pro-Ukrainian battalions.
“My family don’t support me, but they try to understand,” he says. “It’s tough, though. An eternal conflict.”
He doesn’t worry that his presence could lend credence to the Kremlin line about fascists fighting for Ukraine.
“Russia doesn’t need to film my T-shirt to feed their propaganda,” he says.
“They’ll say whatever they want.”
Nearby, Sjoerd Heeger, 22, grasps an AK-47 assault rifle and surveys no man’s land through orange-tinted sunglasses.
A former trash collector and call center worker, he is the butt of relentless teasing as an archetypal war tourist.
“My mum doesn’t know I’m here. Maybe I’ll send her a photo of a grenade. She’s used to me disappearing,” he says.
Heeger’s combat training consisted of firing off just four magazines.
His instructor taught him first aid, “but I didn’t understand half of what he said.”
The unit’s commander welcomes such adventurers.
“The more the better,” says Vano, 28, whose real name is Ivan Borisenko.
“Sure, the Dutch kid doesn’t know how to use his weapon. But he’ll learn soon enough.”
Two men from the Caucasus nation of Georgia, Alkandil and Viktor, hold a neighboring position.
Since the 1990s they have fought against Russia in conflicts scattered around the former Soviet Union: in Abkhazia, Chechnya, South Ossetia and now Donbass.
With his bushy white beard and bulging belly, Viktor, 56, resembles Santa Claus in camo.
“Here, we have one enemy,” says his compatriot Alkandil, 47.
“I hope one day this war will end. I hope one day to hang up my weapon and return home. But while Russia threatens these lands, I will have no peace.”
An hour’s drive from Marinka, in a run-down warehouse that serves as a Right Sector base, several dozen fighters distract themselves from the tedium of a protracted war, cleaning weapons, working out or drinking.
Rusted trucks litter the yard. Patriotic heavy-metal music blares through dank corridors.
A former history teacher services a Soviet-era rocket launcher on a pool table.
Right Sector’s sources of firepower are obscure but have been boosted by black-market deals, battlefield spoils and raids on arsenals.
Beyond the base, PR is not top-priority.
“We don’t get on with civilians here,” says Misha Ukhman, a former journalist who is the group’s media officer.
“We don’t have time for winning hearts and minds. There’s a war to fight.”
Right Sector’s opposition to Ukraine’s ruling elite and desire to revolt is a gift for the Kremlin.
These dissidents could be exploited by the very enemy they fight.
“Right-wing radicals are fertile ground for Russia’s campaign to destabilize Ukraine,” says political analyst Likhachev.
“Their ideology is inherently anti- Russian but shares common goals with Moscow.”
Regardless, rogue militants such as Misha think this is a war that can have no political solution.
“We need another revolution,” he says.
“Politicians steal and steal. We cannot trust them. This is our land. We will fight to the end.”