The front lines where Ukraine and its allies had hoped for a summer breakthrough now epitomize the bleak, dark winter ahead — of Russian resurgence and Kyiv’s mounting losses.

“As we like to say in the army, the plan was good on paper, but we forgot about the trenches,” joked Ihor, a commander in the 15th National Guard. CNN is only using his first name to protect his identity for security reasons. Speaking with CNN deep in a command post in Orikhiv, in southern Ukraine, he is interrupted by panicked noises in the radio room.

The Ukrainians face relentless waves of Russian convict recruits, properly trained and equipped, backed by armor, and often – they believe – given a mix of drugs to bolster their attack. Ukrainian soldiers showed CNN drone footage of an injured Russian, his legs severed, yet a ghoulish smile on his face, seemingly oblivious to the pain.

Those fighting in besieged Ukrainian trenches say they now face another threat: the use of gas as a weapon. Nine incidents have been recorded in recent weeks in this area, one Ukrainian combat medic told CNN, in which a caustic and flammable gas had been dropped by drones onto Ukrainian lines, causing one fatality. The gas is used to cause panic and followed by conventional shelling or drone attacks, soldiers impacted said.