It was early morning and sniper Wali, his Canadian compatriot and two Ukrainian soldiers were in and around a trench at the far end of a wooded windbreak separating expansive farm fields in eastern Ukraine. Huddled among leafless trees, they were essentially the point men in the defence of a village on the approaches to the strategic city of Mariupol. Russian troops and tanks were staging a measured advance across the fallow fields on three sides. Mud was about all that was keeping the heavy armour, visible a kilometre away, from overrunning their position in a 20-metre-deep wood that ran in an angular L-shape, its short leg jutting northeastward toward the enemy. Fresh out of blankets, their bodies warm in the cool morning air, Wali—the nom de guerre of a Montreal-born veteran vo...