Sentenced to Be a Hero, Vol. 3 (light novel) — Rocket Shokai

The Second Capital has fallen to the Demon Blight, and it's up to the combined forces of the Noble Alliance, the Ninth Order of the Holy Knights, and Penal Hero Unit 9004 to retake it. But first, they must establish a base on snowy Mount Tujin, facing legions of faeries along the way. And once again, the heroes take the most dangerous role -- serving as decoys! Meanwhile, as things on the battlefield take a grim turn, a pair of refugees stumble through the freezing wilderness, holding an important key to winning the war ahead.