SULYHIVKA, Ukraine—The messages arriving on Viktor Yatsunyk’s phone were vague and worrisome. Somewhere nearby, Ukrainian soldiers had triggered a land mine and lay dead or injured.
The onetime carpenter and his teammates, who included a store-sign maker, a boxing enthusiast and a computer-science student, converged on a map reference in a beat-up crossover and a pickup truck.
When other army units needed something hazardous done on the eastern front, they called this group. The team of more than 100 had retrieved bodies from no man’s land, led assaults on villages and crept through forests to hunt Russians with aerial drones. And they had won, repelling Russia’s advance in Ukraine’s northeastern Kharkiv region.
Viktor wrote to one of the group’s commanders on the Signal messaging app acknowledging, with a code, the information and the task. “++,” he typed.
The 44-year-old led seven soldiers in single file along the edge of a field in search of the casualties. A Wall Street Journal team followed behind.
The men knew the villages and fields in the area well. When Russian troops were around, a hamlet to the south had become the team’s home, and the forests and fields their terrain.
Viktor, who had served as a reservist in the British army, was a leader within the group. Known as Britanets, or Brit, for his secondary allegiance, he had lived in the U.K. for a quarter-century and received a British passport. He spoke with a London accent and served guests tea with milk. But his mother, who raised him alone with a passion for Ukrainian folk songs, had instilled in him a patriotism that never faded.
When the war started he headed to Ukraine to fight. The unit he joined in the east was dominated by men who made up for their limited military experience with bravery that verged on recklessness. The group was named Skala, or the Rock, after its leader, a giant army major with a passing resemblance to the actor Dwayne “The Rock” Johnson. He pulled together men of similar spirit from wherever he could, and provided them with a steady supply of equipment and food.
The recent Russian retreat had eased months of high tension. That September day, some of the men weren’t wearing body armor. Some wore T-shirts. One waved a metal detector, but it wasn’t much use and he stowed it.
As the team walked along the road, they passed burned-out armored vehicles, antitank mines and discarded weapons and clothes. Recent rain had turned the path to thick mud, which clumped on the men’s boots as they walked. Where recently artillery and tank guns had raged, there was little sound but for a light breeze in the trees.
The team approached a curve about 500 yards down the track. I assumed the casualties would be around the bend.
An explosion flashed, cracked and shook the ground. I ducked instinctively, even though it was little more impressive than a large firecracker.
The echo of the blast faded to silence. Smoke drifted in from the trees to the right. Several soldiers had dropped to the sodden earth. Britanets lay motionless on his left side. Surely they will get up, I thought.
Over 10 months, Ukraine has stunned the world with its military success, which includes reclaiming half the territory it lost during the initial phase of Russia’s invasion.
The Ukrainian effort relies heavily on volunteer units grafted onto the professional army. A novel military experiment driven at first by expediency, the decentralized command has since given Ukraine a crucial advantage in tackling the lumbering Russian military.
The units are often named for their commanders, such as Skala. They work with volunteers who raise funds and provide equipment, such as drones, power banks and pickup trucks. The soldiers are enlisted and follow the standard chain of command, but have broad latitude to pick tasks, coordinate with other units on the ground and figure out how best to get jobs done.
Ukraine has plenty of experienced soldiers—it has fought a low-level war against Russian paramilitaries in the east since 2014. But Russia is girding for a protracted conflict, calling up 300,000 reservists and moving the economy to a war footing. Ukraine can’t afford to lose personnel through carelessness.
As many as 13,000 Ukrainian troops have been killed, officials say, and tens of thousands more have been wounded, taken prisoner or are missing. Many are inexperienced former civilians who learned on the job. Of eight members of one team in Skala’s group, only two remain at the front. Three have been killed, two are no longer physically fit for service and one is recovering in the hospital.
Members of Skala’s group sport badges emblazoned with two antitank weapons and a drone. Asked about the most important asset of his unit, Skala said: “My people.”
“For me as a commander the main thing is to keep my soldiers alive and to defeat the enemy completely,” he said.
It was a few days after Russia invaded on Feb. 24 when Viktor left the farmhouse where he lived in Oxfordshire, England, to head to war. He wasn’t the type to sit idle when something needed doing, his wife Yulia told me. On a visit to the care home last December where she worked, he told her he didn’t want to end up like the old folks sitting silent and immobile.
“I want to die like a hero so my kids know I did something for the country,” he said.
“What are you talking about?” Yulia retorted. “Nobody’s going to die in a war. Who wants to start a war these days?”
After Viktor headed to the airport, Yulia felt confident he would be OK because he was always careful. In his job as a carpenter he would repeatedly check measurements before drilling a hole, she said.
Arriving in Ukraine, where he became Britanets, he joined with James Vasquez, a retired U.S. Army staff sergeant from Norwalk, Conn., who had come to volunteer his fighting skills. They hit it off and headed to Kyiv to join some of Britanets’s friends, who were based out of an auto-repair shop. They started ambushing Russian units with the help of antitank missiles. It was this kind of entrepreneurial warfare that characterized the early stages of the conflict.
Their comrades had little experience. One wore sneakers and a bright red top into early battles. “You are going to get us f—ing killed!” the American admonished him.
After one skirmish, Britanets shot a video of his U.S. teammate standing in front of a destroyed Russian tank. “Welcome to America!” Britanets called out from behind the camera.
Britanets would call Yulia on WhatsApp, his eyes shining, and gush about his teammates and the feeling of camaraderie.
“I can’t believe you went to Ukraine, to a war, where people are dying, and you’re so happy there,” she told him.
After Russian forces retreated from Kyiv at the end of March, Britanets headed east to Barvinkove, a town of some 8,000, named for a 17th-century Cossack leader who founded it as a stronghold. For the Russians it was a new target.
If Russia could take the town, they could strike south and link up with troops slicing northward. That would trap some of Ukraine’s best military units in the east, where many had been fighting for years.
Britanets joined a crew whose job was to stop them. It was commanded by 33-year-old Maj. Yuriy Harkaviy, or Skala. He and a couple of dozen men had started out the war ambushing Russian tank columns. Now they were helping Ukraine’s 93rd Brigade, a battle-hardened mechanized unit, to keep the Russians north of Barvinkove.
The area saw brutal fighting during World War II and is dotted with memorials. Before the war with Russia, volunteer search teams would still dig up remains of bodies from the black earth.
Skala needed more men. He dispatched an aide to scour enlistment offices for suitable recruits. A local member of his team came across a group of soldiers in a house in Barvinkove attached to no official unit.
The team of eight had arrived from Kyiv. They had served in a volunteer unit named Brotherhood, whose leadership professes a far-right religious nationalism. Many of the men had signed up mainly because it was the quickest way to get their hands on weapons.
Among them was Ivan Shpylyevoi, 32, a gruff boxer who worked in online advertising. Ivan had recently switched from speaking Russian, his mother tongue, to Ukrainian. His mother had brought him up alone and they still lived together. He had started running with a bad crowd in his early 20s and getting into fights, his mom said.
After one trip to pick him up from the police station, his mom sat him down: “In life, I can only help you once, then you’re on your own,” she told him.
Something clicked. He distanced himself from the troublemakers and took up boxing more seriously. Around that time, an elderly neighbor approached his mom. “I want to thank you for your son,” the man told her. Ivan, he said, had fought off some teenagers who had tried to rob him.
At the start of the war, after three days trying and failing to enlist at a recruiting office, Ivan jumped on a train to Kyiv, and signed with Brotherhood. He was soon joined by an 18-year-old camp counselor and trainee auto mechanic called Denys Pankevych. They bonded the first night, sharing a laugh about how Denys had accidentally discharged his rifle into a wall of a university lecture hall where he had been billeted in early March.
Denys took the alias Kontrabas, which means cello but is also slang for contraband, because he used to smuggle cigarettes into Poland. Ivan became Sadist for his stern demeanor and the colorful descriptions of his plans for the Russians.
The reality of war stunned them at first. On an early mission to recapture a village, Kontrabas recalls taking cover from mortar fire behind a wall for 15 minutes in a stupor. “I prayed to everyone I could remember,” he said.
He decided he could just as easily be killed cowering in a bunker, so it was better to fight. He stepped out and began copying the more experienced fighters in his unit. The battle for the village lasted all day, ending with a Ukrainian success.
The group Skala inherited was a mixed bag. There was also Radek, a laconic 39-year-old Polish military veteran. Why was he fighting? “Right thing to do,” he said later. (The Wall Street Journal agreed to use only his first name.) The informal leader was 39-year-old Kostyantyn Rusanov, who lived in a Kyiv suburb with his wife and daughters of 11 and 13, where he ran a business selling store signage. When he enlisted and was asked for his nom de guerre, he responded “Nema,” meaning, “I don’t have one.” It stuck, as Nemo.
“Think hard if you are ready for this,” Skala told them. “It won’t be easy.”
Skala assigned the group a commander from his team and sent them on their first mission in May—to recover the body of a scout from the 93rd Brigade. The team set out on foot using a quadcopter drone to scan for the enemy. They took a rope with them, fearing the Russians could have mined the body. They located him, tied the rope around, and tugged. No explosion. They pulled him onto a stretcher and began to withdraw.
Suddenly, the rifle of one soldier caught on his belt and discharged a round. The noise apparently alerted the Russians, and a firefight broke out with the infantry from the 93rd Brigade, who had followed Skala’s men with the aim of digging a new forward position.
They got away with no losses—by sheer chance. “No one died, there was just a fight, and that’s it,” Nemo said.
Russia had an overwhelming advantage in artillery, firing around 10 shells to every one from Ukraine. Ukrainian forces, short on ammunition, focused on accuracy instead, often using drones.
Day after day, Nemo and his crew would head out in a pickup truck, then continue on foot into territory between the front lines to scout Russian positions. They would send the drone up to look for targets and report them back to HQ, a house in a village south of Barvinkove, where commanders would relay the data to artillery gunners. The gunners would correct their own fire from a live stream broadcast from the drone using Elon Musk’s satellite-based internet system, Starlink.
They began losing teammates, including Keks, or Cookie, a pilot, who rushed out on his own with a drone to locate a Russian tank. He had just gotten out of his car when a round exploded nearby, killing him. Another, Shram, or Scar, was sidelined by the lingering effects of injuries from a motorcycle accident he had suffered before the war. Rosomakha, or Wolverine, also quit because of old injuries.
Kontrabas was picked as a drone pilot. He would rather have been on an assault team, he said, for the thrill. When at home he drove at more than 120 miles an hour. “There are no healthy people at war. We are all addicted to something,” he said.
He grew close to Sadist, who became like an elder brother. Sadist had a hard shell but a soft side for those he allowed close. Kontrabas made a video of himself goofing around in a van to music with a cigarette hanging from his lips. Sadist, sitting alongside, glances at him then smiles.
Sadist shot a film of Kontrabas flying a drone. “Our pilot at work. What a hooligan!” he said. “Our little gem.”
Skala’s group had grown in size to more than 100 fighters. In the summer, the Ukrainians went on the offensive. They carefully prepared an assault on Dibrivne, a village to the north of Barvinkove, which would give them access to higher ground.
Nemo’s crew spent five days scouting the village. They located Russian armored vehicles and positions, and directed artillery to hit them. They would spend hours recording video so they had a better idea of the lay of the land.
Soon, Nemo felt he knew exactly where the hide-outs were. He told Skala they were ready to go.
The assault was led by small groups of Skala’s men, followed by troops from the 93rd Brigade, who were supposed to thrust into the village on foot and meet in the center. Nemo’s task was to lead the infantry to the village, using the knowledge he had gleaned.
As Nemo’s team approached a forest packed with concealed Russian positions, they heard the sound of explosions from the trees. The Russians were fleeing, and in such haste that they triggered their own booby traps.
The Ukrainians entered the abandoned village unscathed. From the heights nearby, they were able to strike farther and more accurately onto lower ground around other Russian-held villages. On one occasion, Kontrabas flew a drone 6 miles, a record for Skala’s pilots, to provide footage that helped artillery gunners destroy several Russian tanks.
On Sept. 10, Nemo and Kontrabas went to scout enemy positions in Brazhkivka, one of the Russian-controlled villages, but couldn’t find any Russians there. “Where the hell are they?” Nemo asked. The Russians had fled.
The mood in Skala’s group was celebratory. They sped around the villages hunting for trophy vehicles left behind by the Russians and toured the places they abandoned.
At the village HQ, Britanets received a fresh consignment of equipment from volunteers with garrulous enthusiasm. He offered cookies and tea—“PG Tips or Yorkshire?”—to his guests, which included the Journal team.
Britanets paused now and then to field calls from men working farther east, where the Russians were trying to break through.
He commiserated with me, a fellow Brit, on the death of Queen Elizabeth II. “A good lady,” he said. He shared military banter with Journal security adviser Lee Brett, a former U.S. Army ranger whose job was to keep the reporting team safe.
Britanets showed us his freshly issued American M4 carbine and complained that it needed more accessories. He stowed it in a case. Then he fetched his Ukrainian-made Vulkan assault rifle and offered it to me to feel its weight. He laughed when I pulled my sleeves over my hands so as not to leave fingerprints.
He took back the weapon and laid it on top of a map marked with Russian positions. I continued to question him about how Skala’s group were using drones. The gun was pointing toward Lee, who raised his eyebrows.
“Oh sorry, mate,” Britanets said. “It’s empty.”
He pulled out the magazine to check the chamber. There was no bullet in the chamber, but the magazine was full.
“Running through your NSPs,” Lee noted, referring to Normal Safety Precautions, a set of basic drills to ensure a firearm is safe.
“Yeah,” said Britanets, before returning to the theme of drones.
Ukraine, he said, needed more equipment from the West because it is like a bodyguard standing between Europe and Russia. “What a price Ukraine pays,” he said.
The Ukrainians’ celebratory mood was broken on Sept. 17 by a call from an officer from the 93rd Brigade.
Two officers, a combat engineer known as a sapper and a driver had triggered a mine while scouting for the bodies of men lost during the summer, the officer told a top aide to Skala. Could Skala’s group send a team?
“Britanets, you’re in charge,” said Skala. Britanets pulled on his body armor and helmet.
Just then, our team arrived back at headquarters. “I have to go,” Britanets told me as he walked past.
He jumped into the Kia crossover of a local man who would drive. Three others squeezed in the back: Metr, or Meter, a giant 23-year-old with long hair tied back beneath a bucket hat; Biliy, or White, a computer-science student who played guitar in a funk-jazz band; and Zheka, a thickset man who had been unsteady since he suffered a concussion and had asked not to be sent to the front lines.
The four-person Journal team followed behind with a local video reporter. Britanets tried to call the sapper, who was uninjured, for updates on their position, but couldn’t get through.
We edged across a damaged bridge, then turned right onto a muddy road toward the village of Brazhkivka, where Britanets had raised the Ukrainian flag days earlier. The cars slid from side to side on the muddy road, past two dozen or so incapacitated Russian armored vehicles.
The cars arrived at a fork in the road. One track led left back into the village. The other went straight, with a line of trees to the right. A green pickup sat at the junction with Nemo’s crew—Sadist, Radek and a recent recruit called Chekh, or Czech.
The teams got ready to go. Metr searched, without success, for a USB-C cable to launch a drone. A view from the sky would have told them that the sapper had already dragged the injured man out toward the road we had just left, and that both were safe. Instead, the teams were relying on an outdated map.
Britanets told Nemo he knew the area, Nemo later recalled. “You lead, then,” Nemo told him.
Britanets instructed everyone to leave their weapons in their vehicles. They would likely be pulling people out and would be better off with less gear. He left his helmet behind, as did the others. Some, including Sadist, weren’t wearing body armor. This wasn’t their standard practice.
The soldiers set off along a path between the trees and a field, then turned down an embankment and onto a dirt track.
Britanets turned around to the single file behind him. “Don’t walk too close,” he yelled in English.
The ground was heavy from recent rain and it caked on our boots. After a couple of hundred yards, we came across a line of antitank mines, green metal disks the size of pizzas with fuses in the middle. They are detonated by the weight of a vehicle and can be safely maneuvered around on foot. We shuffled past.
Radek, the Polish veteran, swung a metal detector in front of him. It beeped constantly, rendered worthless by the amount of shrapnel littering the ground. He turned it off. Sadist picked up a Russian rocket launcher as a trophy.
In the lead, Britanets approached a bend. He must have not seen the copper wire in front of him, which was attached to an anti-personnel mine, a rectangular plastic box about the size of a purse. It was concealed behind the grass among the trees 10 yards to the right, its scissor legs dug into the earth to hold it in place.
As Britanets’s leg pushed on the wire, it pulled a pin in the fuse, which released a spring-loaded striker that slammed into the percussion cap and fired the detonator. That set off the charge in the mine and propelled hundreds of tiny pieces of metal in an arc toward Britanets and the soldiers behind him.
Several crumpled to the ground.
All was silent. Britanets didn’t move. Then someone cried: “I’m hit.”
The uninjured men swarmed around the stricken. Nemo, seeing blood soaking the right side of his shirt and pants, managed to tourniquet his leg and arm with help from Metr.
Sadist rose to his knees, grasping his gut. Radek clutched a piece of gauze to his face to try to stem bleeding from his mouth.
Our team had crouched down when the blast hit and remained still, apart from the photographer, who stood up to capture the scene.
“Help us,” Zheka yelled, his eyes wide.
“Stay here,” Lee told us firmly, concerned for our safety. He was worried another mine could be triggered as the men scrambled to help the wounded.
“Check Britanets,” someone said.
Metr walked over and peered at him.
“Half his head is gone,” he cried.
The men couldn’t figure out how to carry out the injured with only three fully healthy soldiers.
“We’re going to have to help carry them,” I said to Lee. I paused: “Well, you tell me.”
“No,” he said. “No. I need you guys out.”
Lee stood up, turned around and went first, inching along the footprints we’d left, checking for more booby traps.
We had got only a few yards when Zheka yelled: “Press! Turn around and come and f—ing help.”
I looked back and saw him struggling to support Nemo, who was limping badly and howling with every step.
“Can I help him with the guy on his shoulder?” I asked Lee. Lee didn’t object.
I put my right arm under Nemo’s left shoulder and around his back. My right hand gripped his clothing damp with blood.
“It’s not far,” I told him as we set off.
I asked his name, told him mine, and asked whether he had children.
“Yes, two,” Nemo grunted.
“OK, we’re walking to your children,” I said.
We found a slow but steady rhythm. His weight dragged down my right side and grew heavier with every step. I tried to keep us moving in a straight line on the trodden path, worried about more mines if we strayed.
We had walked for several minutes when we spotted three armored vehicles laden with soldiers chugging along the track. We halted, and I called for help.
Nemo was weakening. I shoved my shoulder deeper under his to support his weight better. I was panting now. “Come on, you can do it,” I said, to him—and to myself. We made it a few more yards before he collapsed to the ground.
Several of the men had jumped off the armored vehicles and charged down the bank. They began to tend to Nemo, so I scrambled to the relative safety of the track.
Lee was there treating Radek, who had blood dripping from his mouth. A metal fragment was lodged inside. Lee told him to sit and wait for evacuation.
Back where the mine went off, Zheka, Metr and Biliy were struggling with Sadist.
“Guys, I’m f—d, you can just leave me,” Sadist said between groans, Biliy told me later.
They tried to load him on a lightweight canvas stretcher, which ripped. Sadist was covered in mud.
Zheka lifted Sadist’s legs onto his shoulders and Biliy tried to raise his body. “Why are you carrying me?” Sadist protested. “Put me down!”
The troops from the vehicles brought a stretcher and carried him to the road. His face was white, his mouth open and features contorted.
The soldiers laid the stretcher down and we went to help—Lee to provide treatment, me to assist and interpret.
“Keep him steady for me,” Lee said, lifting up Sadist’s T-shirt. A small slit was visible around where his liver was. A tear of blood seeped out.
We rolled him onto his side to check his back for an exit wound. There was none. The fragment must have sliced up his insides.
The muscle-bound boxing enthusiast Sadist was fading. He was no longer speaking Ukrainian but had reverted to the Russian that his mom spoke to her little boy, Ivan.
“Please,” Ivan said weakly. He was clawing at his pants trying to release the pressure from the blood pooling inside his gut.
“Please. F—,” Ivan pleaded, suddenly thrashing with his arms as if trying to haul himself up. “I can’t lie here.”
We pinned his arms and Lee started to apply a bandage and tried to comfort him. We had done what we could.
We went to check on the other casualties. Nemo’s leg wound wasn’t serious, which meant the blood covering him must be coming from his arm, where the tourniquet was loose. Biliy held him from behind and I gripped his arm tight as Lee pulled off the bandage. Blood squirted a foot in the air.
“Tell him this is going to suck,” Lee told me. He took a wad of gauze designed to stop bleeding and shoved it into Nemo’s arm. Nemo screamed.
Lee wrapped a bandage over the top and secured it. “Done, done,” he told the soldier. “The good news is, you’re going to live.”
Lee bandaged up the minor leg wound of Chekh.
Biliy cradled Sadist. He was dead.
Some soldiers lifted him from the stretcher onto a blanket with a picture of a lion. His right arm flopped to the side, revealing a tattoo, which read: “Good luck.”
Skala sped up in his black SUV. He looked worried and needed to take control.
Metr had stayed with Britanets at the bomb site. Others worried the mine had been set off by vibrations and that there were more to come. Skala went to fetch his men. The sapper from the 93rd Brigade—the man whose group had sparked the day’s events—went with him. Skala also took a Russian prisoner the group was holding.
“I can’t risk my people,” he said.
They freed Britanets from the wire, which was wrapped around his boot, covered his head, loaded him onto a stretcher, and brought him back to the road. They lifted him onto the back of a pickup next to Sadist, and covered him with the blue canvas stretcher. His striped gray socks poked out from underneath.
Skala had questions for us when we saw him two days later.
“Why did you go onto the field?” he asked. He was worried he had put us at risk. I reassured him that we were doing our jobs and were aware of the danger.
Our presence there concerned him for another reason: Had Britanets been playing to the press and lost his vigilance? “He’s a character,” Skala said.
It was the group’s first loss to a tripwire, he said. He lamented that the men hadn’t been able to launch the drone, because perhaps then they would have seen the safer route via the main road.
“Carelessness,” he said. “We were heroes, real men. We were relaxed.”
Could Sadist have been saved? No, Lee replied.
The day after the incident, Kontrabas called Sadist’s mother and told her that Ivan was dead. He thought the call was better coming from someone who knew Sadist well, rather than from an unknown officer from HQ. When Kontrabas heard his friend’s mother burst into tears, he felt a surge of guilt. He was alive and hadn’t been there to look out for his friend, who had saved him earlier in the war.
Ivan died as he wanted, his mom said, recalling his words before he set off in February: “Mom, if I die at war, it is the death I want most of all.”
Radek had several operations over the following weeks. The fragment had hit a nerve, paralyzing his face. He had to learn to talk and eat again.
He said lack of training, poor midtier command and a lack of professionalism were costing Ukraine dear. The men were brave, he said, but they were being thrown into a meat grinder that was chewing up young men and experienced fighters.
He said he would go to the front when he recovered. “No romanticism here,” he wrote in a message, “just pragmatism.”
Nemo recovered well. By December he was back on the front lines in the east. “Who else is going to do it?” he said.
Shortly after he returned, another of their crew, a man in his early 30s named Arkhip, was killed in fighting. That left only Nemo and Kontrabas from their original group of eight from Brotherhood still at the front.
In England, Yulia mourned Viktor, Britanets. She knew him as a gregarious but meticulous man. She wondered—had he been so focused on the task of saving others that he had overlooked his own safety?
Viktor’s ashes were buried in his grandmother’s village in western Ukraine, where he had planned to retire with Yulia and renovate his ancestral home. The local mayor granted permission for him to be buried at a memorial for heroes of attempts to establish a Ukrainian state in earlier centuries.
Viktor’s mother fell to her knees in tears in front of the grave. Then dozens of mourners broke into the Ukrainian national anthem, a defiant ode to the price of liberty that includes this penultimate line: “We shall lay down our souls and bodies for our freedom.”
Oksana Grytsenko, Kate Vtorygina and Ievgeniia Sivorka contributed to this article.
Write to James Marson at james.marson@wsj.com