They Are Russians Fighting Against Their Homeland. Here’s Why.

The soldier knelt in the snow, aimed a rocket launcher and fired in the direction of Russian troops positioned about a mile away. He was set up at a Ukrainian firing position, and looked just like the other Ukrainian troops fighting south of the city of Bakhmut in one of the most brutal theaters of the war.

But he and his comrades are not Ukrainian. They are soldiers in a Ukrainian military unit made up entirely of Russians who are fighting and killing their own countrymen.

They have taken up arms against Russia for a variety of reasons: a sense of moral outrage at their country’s invasion, a desire to defend their adopted homeland of Ukraine or because of a visceral dislike of Russia’s president, Vladimir V. Putin. And they have earned enough trust from Ukrainian commanders to take their place among the forces viciously fighting the Russian military.

“A real Russian man doesn’t engage in such an aggressive war, won’t rape children, kill women and elderly people,” said one Russian fighter with the military call sign Caesar, ticking off atrocities committed by Russian soldiers that motivated him to leave his native St. Petersburg and fight for Ukraine. “That’s why I don’t have remorse. I do my job and I’ve killed a lot of them.”

Nearly a year into the war, the Free Russia Legion, as the unit is called, has received little attention — in part to protect the soldiers from reprisals by Russia, but also because of reluctance within the Ukrainian military to highlight the efforts of soldiers whose home country has done so much harm to Ukraine. Several hundred of them are concentrated in the area around Bakhmut, in eastern Ukraine, officials said; they are always grouped with their own but are overseen by Ukrainian officers.

In interviews, some Russian soldiers said they were already living in Ukraine when Russian forces invaded last year, and felt an obligation to defend their adopted country. Others, often with no military experience, crossed into Ukraine from Russia after the war began, moved by a sense that the Kremlin’s invasion was profoundly unjust.

“We haven’t come here to prove anything,” said one soldier with the call sign Zaza. “We’ve come here to help Ukraine achieve the full withdrawal of Russian forces from Ukrainian territory and the future de-Putinizaton of Russia.”

Fearing retaliation against relatives and themselves, none of the soldiers interviewed agreed to be identified by name or to provide specific details about their biographies. Last week, the Russian prosecutor general’s office filed a suit with the country’s supreme court to have the Legion declared a terrorist organization.

Zaza, a skinny blond who looks barely out of high school, would not even give his age, saying only that he was under 20. After Russian forces invaded, he said, he could not keep his mouth shut. His outspokenness and antiwar posts on social media got him in trouble with his university’s administration, then with the police. When officers from Russia’s security service showed up at his front door in the fall, he said, he decided it was time to leave.

He said he walked across the border into Ukraine and signed up to fight.

“At such a young age, it is a little early for me to talk about my political opinions and worldview, because these are just forming now,” he said. “But when your country has been taken over by one bad man, you need to take things into your own hands.” 

At the start of the war, Ukrainian law prevented Russian citizens from joining the armed forces. It took until August to finalize legislation that would allow the Legion to legally join the fight, Andriy Yusov, a spokesman for Ukraine’s military intelligence service, said in a statement.

“There was a large number of Russians who because of their moral principles could not remain indifferent and were searching for a way to enter the ranks of the defenders of Ukraine,” Mr. Yusov said, explaining the military’s motivation to create the unit. “All legionnaires have come with a huge desire to stop Putin’s horde and free Russia from dictatorship.”

The group operates under the umbrella of Ukraine’s International Legion, a fighting force that includes units made up of American and British volunteers, as well as Belarusians, Georgians and others.

It is not easy to join, Russian soldiers said. They have to submit an application and undergo an extensive background check that includes polygraph tests. Only then can they enter basic training. As Russian passport holders, they are inevitably met with distrust. There have been several attempts by Russian spies to infiltrate the Legion, Mr. Yusov said.

In a pine forest in the Kyiv region last week, a group of new Russian recruits nearing the end of a three-month basic training course practiced tactical retreats, firing mortars and basic combat medicine. They exemplified the international hodgepodge that has come to define much of Ukraine’s war effort: Russian soldiers trained on a French-made 155 millimeter mortar and carried American-made M16 rifles.

“It’s better than a Kalashnikov,” one of the soldiers said of the M16. “I’ve fired about 1,000 rounds and haven’t had any problems yet.”

The sounds of small-arms fire and heavy artillery echoed through the forest, and an instructor threw a dummy grenade near a small group of soldiers to gauge how they would react. Most of the soldiers will occupy positions back from the front lines, working in artillery or air reconnaissance units using drones.

Though the instructors were all Ukrainian, all spoke in Russian. In interviews, some of the recruits tried to speak a few words of Ukrainian, but quickly switched back to their native language.

“After about one or two months as they’ve settled in, they start to use small phrases like ‘thank you’ or ‘fire,’” said one of the instructors, who declined to provide his name.

The soldiers said they struggled to explain their decision to family back in Russia. Reports of atrocities committed by Russian troops, including the butchering of civilians in the Kyiv suburbs of Bucha and Irpin, are dismissed as foreign propaganda in their homeland.

“They don’t understand the whole truth,” said a 32-year-old soldier with the call sign Miami, who said his parents had urged him to fight on the Russian side. “They’re told that bad people live here, and they believe it. They don’t believe that the second biggest army in the world could kill regular people.”

Back at the front in eastern Ukraine, the shelling never stops for long. Russian forces have been hammering away at Ukrainian positions, trying to dislodge them around Bakhmut in advance of an expected offensive push to take all of the eastern region known as the Donbas.

On a recent visit to a firing position, the precise location of which The New York Times is withholding for security, the ground rumbled and artillery shells crisscrossed a clear sky. That day, Russian forces had launched a volley of grad rockets that blanketed the area, wounding several civilians but sparing the soldiers.

“They’re striking everywhere,” a panting Russian soldier said as he took cover in a dugout in a neighborhood of small, snow-covered cottages.

Soldiers in the Legion said that they were continuing to hold the line, but some have already begun to think beyond the immediate battle, and even beyond the war in Ukraine, to what comes next.

“My task is not just to protect the people of Ukraine,” said Caesar, 50. “If I remain alive after this phase and all Ukrainian territory is liberated, I will absolutely continue fighting, with a weapon in my hand, to overthrow this Kremlin regime.”

Caesar, who has earned a reputation as a kind of eccentric sage within the legion, said he was an avowed Russian nationalist. Yet he nonetheless believes that modern Russia has gone off the rails, particularly when it comes to invading Ukraine, he said.

He was once a member of the Russian Imperial Movement, which the United States has declared a violent extremist group, but said he broke with it in part over its support for Russia’s annexation of the Crimean Peninsula in 2014.

A senior Ukrainian military official involved with overseeing the Legion said that Caesar “had spent a long time searching for a path he felt was ideologically correct,” adding that Ukrainian officials had found no reason to distrust him.

Caesar, who moved his wife and four children to Ukraine over the summer, said he did not believe he was fighting against fellow Russians, but “scoundrels and murderers” who have no nationality.

“I’m sitting before you, an example of a Russian man, and an example of a man that Tolstoy and Dostoyevsky wrote about,” he said. “That’s the kind of man I am. Not them. They aren’t Russian.”