By Simon Lewis THE IZIUM FRONT, Ukraine (Reuters) – Barely a kilometre from Russian positions defending the captured eastern city of Izium, Ukrainian and foreign fighters hunker in a dank basement. Artillery rains down on them most nights, shaking loose the plaster and filling the air with dust. At the sharp end of efforts to stop the Russian army’s progress in eastern Ukraine are the Carpathian Sich battalion, a unit of Ukrainians and foreign nationals who answered Kyiv’s call for help to confront the invader. “Now it’s more of an artillery war. It’s a tougher war, a scarier war, where only p…