Mark Gregory Paslawsky, the sole American fighting on the Ukrainian side of the war in the east of the country, died from injuries sustained in battle in the town of Ilovaysk on Tuesday.

Known by the codename "Franko," the 55-year-old investment banker was a Manhattan native, and had a slight limp and a pronounced New York accent, making him seem an unlikely candidate for a soldier in an eastern European war that has already claimed more than 2,000 lives.

VICE News interviewed Paslawsky in early August in the Luhansk region where he had been deployed with the volunteer Donbas Battalion. He said he decided to take up arms against the separatist Russia-backed rebellion because of his family's Ukrainian background, as well as the frustration and helplessness that came with watching news reports on Ukraine's deteriorating situation after Moscow's annexation of Crimea.

'The whole platoon says "fucking" every other word, we got it from him. He used to say "fucking Obama" all the time, because the US hasn't given Ukraine any support.'

Paslawsky worked in the financial sector and was based out of Kiev, Kharkiv, and Moscow for many years before he joined the Euromaidan protests that gripped the Ukrainian capital last winter. Most recently, he was an independent investment advisor.

"Given what I saw, the level of incompetence, the corruption, the lack of activity — I just decided that I needed to go and participate. If there was ever a time to help Ukraine this was the time to do it," he told VICE News.

After graduating from West Point, Paslawsky served in the US Army Rangers until he was 32 years old.

Oleg Nikitin, Paslawsky's friend and former colleague at Avec Holding in Kharkiv, told VICE News: "He didn't have the patience to sit and watch the chaos that was happening [in Ukraine], and as a professional soldier, he didn't need much training and was in good physical shape. He made the decision to join up conscientiously."

"I think he had been a major, but he never talked about it," a member of Franko's unit who goes by "Lex," told VICE News. "I got the feeling he was very wealthy, but he made a point of trying to hide it. He never used his money and insisted on carrying only the equipment he was issued with by the battalion."

When asked if he had a wife or children, Paslawsky told VICE News, "No. I'm not crazy like that, I wouldn't be here if I did." He was survived by his mother, sister, and brother.

Mark Paslawsky (second from right) with the men of his unit on guard duty at the television tower in Artyomovsk, Donetsk Region, in July.

Ukrainian forces have battled separatist rebels to capture the town of Ilovaysk for the last three days in an attempt to cut the rebel capital Donetsk off from the Russian border and supplies. Maxim Dondyuk, a Ukrainian photographer embedded with the Donbas Battalion, told VICE News that he saw an injured Paslawsky brought back to a school the battalion is using as a temporary base on Tuesday.

"He had three wounds in his back," Dondyuk said. "He was saying that he was in pain and that he didn't want to die. People were telling him he was going to be okay. I think it might have been possible to save him if we had medevac helicopters or ambulances but all there was on hand were the battalion medics."

Three other members of the Donbas Battalion were killed in fighting on Tuesday according to both Dondyuk and Donbas spokeswoman Vasilisa Trofimovich. Semyon Semenchenko, the battalion's commander, was hospitalized with multiple shrapnel wounds but is in stable condition, Trofimovich said.

'He really hated the Russians. We all hate the Russians.'

"This was a botched operation," Dondyuk said. "Donbas was supposed to fight its way into the city with the support of three other battalions, but they chickened out and now we're surrounded by the separatists and are being shelled with grad rockets and mortars. If they manage to cut off the road leading out of here we're all done for."

Paslawsky spoke both Ukrainian and Russian and served in a unit with five other men where he had a reputation for being a joker. "The whole platoon says 'fucking' every other word, we got it from him. He used to say 'fucking Obama' all the time, because the US hasn't given Ukraine any support, he was really ashamed of that," Lex said.

Paslawsky could also be merciless, however. Lex explained that after capturing eight separatists, half of whom were Russian, a Ukrainian soldier gave one of the prisoners a drag from a cigarette and Paslawsky burst into a rage. "He said, 'Why don't you pour him a shot of vodka as well. These are the guys trying to kill us!' " Lex recalled. "He really hated the Russians. We all hate the Russians."

However, Paslawsky and the other members of the Donbas Battalion weren't just motivated to take up arms by events in the east, which have resulted in chunks of Ukrainian territory being declared independent statelets by armed men from both Russia and Ukraine. Many see another enemy in the culture of corruption among Ukraine's elite.

"When you hear the discussion among the guys — extremely passionate — and it all boils down to this whole thing of corruption and the fact that we've not seen change for 20 years," Paslawsky told VICE News.

He predicted that the volunteer battalions — which have emerged as a formidable force alongside regular Ukrainian troops — would set their sights on the Kiev authorities with a "Maidan 3.0," as he called it, to push for reforms after the war was over.

In a pre-interview before going on camera, Paslawsky also warned that the volunteer battalions could emerge as a dangerous, uncontrollable force that ought to be disbanded and replaced with regular army soldiers mobilized from the general population.

He also added a quick, "Man, I don't know," a deep sigh, and "I hope this whole thing can be over before the end of August." For Franko at least, it now is.