A battalion commander was racing down a road with his men in pursuit of retreating Russian soldiers when he came across an abandoned Russian armored vehicle, its engine still running. There was a sniper rifle, rocket propelled grenades, helmets, and personal items inside. The men had vanished.

“They dropped everything: personal care, helmets,” said Swat, the commander’s code name. “I believe it was a special unit, but they were terrified.” It was pouring heavily, the road was bad, and they dropped everything and moved.”

After months of static fighting and holding the line under withering Russian artillery barrages, Ukrainian soldiers are ecstatic about their three-week-ago smashing of Russian lines in the northeast and recapturing swaths of territory seized by Russian troops earlier this year. They have almost completely retaken Kharkiv Province, as well as territory in each of the four regions that President Vladimir V. Putin claims Russia has annexed.

The Ukrainians have had little time to reflect as they press their counterattack, intent on keeping the pressure on the retreating Russian army and preventing it from regrouping. Yet after months in the trenches never seeing the faces of the enemy, Ukrainian soldiers and commanders have now engaged the Russians up close and gotten a chance to size up their opponent.

Swat, a 58-year-old career soldier, came out of retirement to command the Carpathian Sich, a volunteer battalion, after his predecessor was killed in action near Izium in June.

In recent weeks, the battalion has been at the forefront of the fighting, providing flanking support in battles for the strategically important cities of Izium and Lyman. Four days ago, the battalion seized another town further east, assisting Ukraine in securing a series of dams and the last settlements in northern Donetsk Province.

The battles have been fast paced, causing panic on the Russian side during the flight from Izium. Swat claimed that after capturing Izium, his unit pursued Russian troops for 15 miles down the road in one day. After a few days, Ukrainian troops were at the gates of Lyman, 30 miles south of Izium; Swat’s group moved east to prevent any Russian army reinforcements from arriving.

The battalion then lost five men in a Russian missile strike, and Swat lost a close friend when their car hit a mine after three weeks of sweeping success and minimal losses. Swat was driving, but he suffered a concussion.

When asked about his friend in an interview, he cried and asked that a reporter not sugarcoat events of the war with only success stories.

Russian armored vehicles were defending and firing machine guns, according to Swat. “But everyone was so excited that no one stopped,” he explained. “I was on the run with a pistol.” It’s like a small sense of accomplishment. It’s incredible; you can feel it inside and you’re happy.”

He said the men were firing their weapons and not listening when he ordered them to stop. Given that the Russians were already retreating, it was only a minor firefight, but the capture of Izium gave them a huge boost of confidence. It was vindication for three months of grueling fighting defending positions under Russian artillery and airstrikes, he said.

Some Russians, he said, were ready to give up because they were demotivated, scared, and hungry. But some fought on, believing Russian propaganda that the Ukrainians would torture and kill them if they were captured.

In seven months of fighting, his battalion has taken more than 30 Russians prisoner, 23 of them during the counterattack, he said. “We just get information from them, give them water, food, and warm clothes, and send them up,” he explained.

His men have had a steep learning curve, not only in survival but also in humanity. A 27-year-old American platoon commander from his battalion, who uses the code name Boris, said one of his most intense moments of the war came when he held a cup of water for a Russian prisoner to drink.