(CNN) — A fighter was shot twice and sent from hospital to the front lines, where he drank melted snow to live. The soldier was forced to assault Ukrainian positions repeatedly, until a grenade blinded him. The young man was saved from the trenches by a doctor who turned him into a hospital orderly.

Another man who was jailed at 20 on minor drug charges was sent to the front at 23. With hardly any training, he died three weeks later; he was among 60 Russians likely to have been killed in an assault on the same day that Russia’s President Vladimir Putin celebrated the defeat of the Nazis in Red Square.

These two stories, of remarkable survival and untimely death, epitomize the sordid and grueling loss of life in the Russian trenches in the Ukraine. However, there is a distinction: the dead are prisoners, who are promised a respite from their prison terms if they join the so-called Storm-Z battalions run by the Russian Defense Ministry.

Life expectancy is short, the conditions themselves are difficult to survive, and convicts describe using them as cannon fodder. Tens of thousands of convicts have been recruited to serve on the front lines, initially by the Wagner mercenary group, a scheme later taken over by the Defense Ministry.

CNN spoke to the mother of a convict, Andrei, who was jailed at age 20 on drug charges and sent to the front lines as part of the Russian army’s conscription program. The mother provided extensive videos, documentation, and chat messages to verify the story of her son and her untimely death, just three weeks after deployment.

CNN also spoke to a rare survivor of Storm-Z units, Sergei, who was first interviewed by phone at a military hospital months earlier and last week recounted the deteriorating and wild life in the Russian trenches.

While the appalling combat conditions are well known, much Russian testimony comes from prisoners of war and is provided through Ukrainian facilitators. These two stories represent rare testimony delivered directly by the Russians. CNN changed the names and removed key details from these two accounts for the safety of the interviewees.

Captured Russian soldiers tell of low morale, disorder in the ranks and horrors of trench warfare
russian soldiers
Sergei, not his real name, is seen in a picture provided by him. He says that many of his unit were killed and wounded in fighting in the Ukraine. (Credit: Obtained by CNN)

Sergei now works two jobs to feed his family, but he said he is still waiting for military compensation for his multiple injuries. His ears ring at night from the shock of the shell, making it difficult to sleep in the silence of his home.

He said he received nine concussions from artillery shells that fell near him while he was on the front line, over a period of eight months. Last winter he was shot in the leg and then sent back to the front after 10 days of treatment, he said. They shot him again, in his shoulder, and duly hospitalized him. Two months later, a manpower shortage meant he was sent back to the front, where he said he discovered convict amputees had been assigned radio duties, and troops were discarding their bulletproof vests because they had minimal protective value.

“They don’t help against shells, as their [Ukrainian] artillery hits with great precision,” Sergei said. “Our artillery can fire three or four times and, God willing, something explodes. It’s lopsided and in most cases it hits us first.”

Ukrainian recounts torture by Russian soldiers who forced her to dig “her own grave”
everyday horrors
Casualty rates are hard to conceive of. Sergei said that of his unit of 600 prisoners recruited in October, only 170 were still alive and all but two were wounded. “Everyone was injured, two, three, about four times,” he said. He recalled seeing his colleagues torn to pieces by shells falling near them and his amazement that they had survived. One assault was particularly vivid.

“I remember the last of the nine concussions I had most clearly,” he said. “We attack, few drones for us. Our commander shouts on the radio: ‘I don’t care, go ahead! Don’t come back until you take this position!’ Two of us found a small trench and dove in.”

But his ordeal was not over. “A (Ukrainian) drone threw a grenade at us and it landed in the space of 30 centimeters that separated us. My friend was covered in shrapnel everywhere. Yet I was somehow intact. But I lost the v