Kyiv, Ukraine – When Russia invaded Ukraine in February 2022, 32-year-old Johnny, from St Petersburg, set himself a goal.

He wanted to overthrow Vladimir Putin’s administration.

In fact, he would have liked to kill the Russian president with his own hands, he told Al Jazeera in a cafe at a remote petrol station on the outskirts of Ukraine’s capital.

In October, Johnny joined other Russians fighting for Ukraine and against their homeland as part of the Siberian Battalion, a unit formed last summer by the Civic Council, a Russian opposition group based in Poland.

“We want to democratise Russia. And it won’t be possible in the current state. Russia must fall apart into smaller pieces. I don’t care if it’s going to be small like Belgium … Places like Yakutia and Chechnya and other regions should be able to secede if they choose to,” Johnny said.

According to Denis Sokolov, 54, the group’s coordinator, 50 fighters from the unit are currently in training or battling in Ukraine. Another 40 are being checked over by Ukraine’s security services as they wait to cross the border.

He said there are thousands of other Russians willing to join the fight against Moscow, boasting that the Civic Council receives up to 10 applications per day.

Those who want to sign up must first depart for a third country for safety reasons. And from there, it takes months to process an application.

“Ukrainians do not trust Russians, and there are reasons for this. But this war was unleashed by the regime in our name, and we are obliged to end it,” Sokolov said.

At the time of publishing, neither Polish nor Ukrainian authorities had responded to Al Jazeera’s request for comment on the Civil Council and Siberian Battalion.

Since the onset of the war, hundreds of Russians have turned on their country and bolstered Ukraine’s forces.

According to the International Crisis Group, their motives are diverse.

“Most of the recruits from the Russian Federation hail from the North Caucasus – majority-Muslim regions that have a long history of advocating for separation from the central government,” the group said in October.

“There are also, however, ethnic Russians fighting on behalf of Ukraine. Some are simply sympathetic to the Ukrainian cause or see joining it as a part of their own struggle against Russian President Vladimir Putin.

“Others, however, are far-right activists who hope the war will end with not just the collapse of Putin’s government but also the creation of a new, ethnically homogeneous Russian state.”

The far-right fighters, the think tank said, are the “most battle-ready” of the Russian units.

Russian troops are officially part of Ukraine’s international legion, fighting with the permission of its defence ministry, and using Ukraine’s weaponry.

According to Russian law, the definition of high treason was extended in April to include fighting for enemies – a crime that could result in life imprisonment.

In contrast, the Kremlin has reportedly offered citizenship to foreigners who choose to fight alongside Russian forces.

Johnny, which is a nom de guerre he adopted after joining the unit, waited for seven months to enter Ukraine.

He contacted the Civic Council in March when the group was helping recruit fighters for the Russian Volunteer Corps, a far-right unit behind incursions into Russia in March and May.

The two groups have since parted ways.

The Civic Council decided to form a new, more inclusive unit that would accept non-white and non-Christian Russian citizens.

The Siberian Battalion is made up of an array of people and groups, including anarchists, Muslims and members of the Free Ingria Movement fighting for the liberation of the St Petersburg region.

“People are different. We are of different ages. Our values differ. But we all want to defeat Russia. And we believe that this is possible only by armed means,” said Johnny, who has not told his family about his fighting or whereabouts.

The Siberian Battalion was named after the vast Russian region rich in natural resources, stretching from the Ural Mountains in the west to the Pacific Ocean in the east.

“We understand that all of Moscow’s wealth comes from Siberia and that Moscow – and the rest of Russia – live off of Siberian money,” Sokolov said.

“Taking these resources away from the regime is important because, first, without them the empire will be less aggressive. Secondly, the peoples of Siberia have the right to manage their resources independently, not just Indigenous peoples, but everyone who lives in Siberia.”

The Siberian Battalion accepts people from other regions too, like 26-year-old Siziy, the unit’s medic-in-training who was born in Moscow.

The former customs official, who also ran his own business, arrived in Ukraine on the same day as Johnny and heard about the Civic Council when the organisation was recruiting for the Russian Volunteer Corps.

But Siziy, which is a nom de guerre meaning “grey blue” in Russian, does not associate with far-right nationalism.

In April 2022, he converted to Islam.

His parents found out about his decision when he was already in Ukraine. He has cut contact with everyone he knew in Russia.

While it was not easy to accept that her only child went to war, Siziy said, his mother has not protested against his decision.

“Everyone makes decisions for themselves. I realised that there is something more important than material wealth in this life,” Siziy said. “If there’s one thing to die for, it is freedom. And Ukraine is fighting for existence.”