Vlad, a Russian soldier, was heading from Ukraine back to Russia for a prisoner swap by bus last year when a tall dark-haired man entered the vehicle.

The man said he was the commander of the Russian Volunteer Corps (RVC) and offered the passengers a chance to join his unit of Russians fighting in and for Ukraine against their homeland.

Vlad, 27, raised his hand. He was the only Russian hostage on the bus to do so, joining a group of fighters who had switched sides.

In an interview with Al Jazeera, an RVC spokesperson refused to say how many Russian soldiers have turned coats, but claimed that recruiting Russian prisoners of war (POWs) has boosted their ranks.

Officially created in August 2022 under the command of Ukraine’s military intelligence, RVC is one of the three all-Russian units fighting on Kyiv’s side.

It was founded by Denis Kapustin, also known as Denis Nikitin or White Rex. A former hooligan, mixed martial arts fighter and well-known hard-right activist, Kapustin is barred from entering the Schengen zone for his views.

German officials have described him as an “influential” neo-Nazi activist, according to Politico, which interviewed him recently. He told the magazine that he rather sees himself as “definitely conservative, definitely traditionalist, definitely right-wing-ish”.

In Ukraine since 2018, Kapustin has been organising and leading the militia. His unit, together with the other Russian groups, has made several incursions into Russian territory as part of what they call an effort to liberate Russia from occupiers.

“We are an official part of [the] Ukrainian army but we have serious political ambitions and political agenda – to get rid of [Russian President Vladimir] Putin,” he told Politico.

When Vlad, who was born and raised in the city of Samara, first met Kapustin on the bus, he promised to defend Ukraine and fight for a new Russia.

“I wanted to make up for my past mistakes,” he told Al Jazeera in a cafe near Kyiv. “At some point, I understood that what they were telling us in Russia was a complete lie.”

Vlad said he initially had no plans to join the Russian army.

At a young age, he became involved in the hooligan movement, which was often nationalistic with strains of racism, and at odds with the authorities.

He enlisted in the army when he was serving a prison sentence of three years and eight months for an assault. It was his third stint in prison since he was 15. He was promised that his criminal record would be annulled.

“I wanted to clear my story and leave Russia. With a criminal record, I could not get a Schengen visa to join my parents abroad,” Vlad said.

In 2022, he joined the Wagner Group, the private military company headed by the late Vladimir Prigozhin, a former Putin ally turned insurrectionist, who personally visited Vlad’s prison to recruit fighters.

Each convict was promised a monthly salary of 250,000 roubles ($2,675) along with a combat allowance.

“[Prigozhin] said that he had the authority from the president to take anyone. He asked us to join the fight and defend our homeland. He said there are Nazis and Americans in Ukraine, that children were being killed,” Vlad said.

“We were promised to be put in the second line, in the defence positions. But then, a week later, they started preparing us for the storm. We understood there was no going back, and that we will have to fight till the end. Because if you don’t follow orders, you get shot.”

After two weeks of intense training, Vlad went to the front. But after about six weeks, in November 2022, he was taken by Ukrainian troops and spent nine months in captivity.

Al Jazeera did not find evidence that Vlad or other Russian prisoners of war were coerced into fighting for Ukraine.

However, such a possibility cannot be ruled out.

In November 2023, Russian state media released video footage of Ukrainian prisoners of war swearing allegiance to Moscow amid reports they were being sent to fight for Russia.

At the time, Yulia Gorbunova, a researcher on Ukraine at Human Rights Watch, said while Russian authorities might claim they were recruiting them on a voluntary basis, “it is hard to imagine a scenario where a prisoner of war’s decision could be taken truly voluntarily, given the situation of coercive custody”.

Just like Vlad, before he joined the war, 25-year-old Mikhail Viktorovich Pavlov was in prison.

He was serving a six-year sentence for possession of 9gm (0.32 ounces) of cannabis. He says the drugs were planted to him by local authorities in his hometown, Ivanovo.

He was always vocal about their wrongdoing, and they wanted to silence him.

When Russia invaded Ukraine, and Wagner and the Russian Ministry of Defence started recruiting prisoners to join the war, Pavlov said he began to plot his plan.

While he was against the war and President Vladimir Putin, he saw joining the army as an opportunity to gain freedom and turn himself in to the Ukrainians.

“I understood perfectly well that if you try to desert from Wagner, it will end very badly. It was almost impossible. But the army is very convenient in this regard,” Pavlov, whose call sign is “Pers”, told Al Jazeera in Kyiv.

“If you want to hide or run away and you have your head screwed on, you can do it easily.”

Four years and two months into his sentence, Pavlov was driven to Ukraine’s Luhansk region to join the war in May 2023.

He received training and, after a month, was posted to Zaporizhzhia.

“I collected some important information on the Russian positions, and I moved towards the Ukrainian positions. At first, nobody believed me. I went through all sorts of polygraph, psychological and physical tests. It took a few months but, in the end, they accepted me,” Pavlov said.

Soon after, Nikitin paid him a visit and offered to join the RVC. Pavlov said he has never regretted his decision.

Pavlov and Vlad, now full-fledged members of RVC, say they took part in an incursion into Belgorod last month.

They both claimed to have girlfriends in Ukraine and said they did not want to go back to Russia. Both said they do not miss anything about their homeland.

“From August, when I joined, to the present day, I have realised myself as a human, as a person, much more than in the 24 years of my life there,” Pavlov said. “Unfortunately, Russia could not offer me anything.”