Valhalla is a world of endless winter, locked in a killing cold ever since a wandering asteroid struck the planet and threw its climate into permanent glacial night. What had been a temperate world became a frozen waste of ice-plains and blizzard-scoured tundra, forcing its people to abandon the deadly surface and burrow deep, building vast subterranean hive-cities warmed against the eternal freeze above.
Life in these cramped, crowded warrens bred a people of grim endurance, patience, and communal discipline, accustomed to scarcity and to the constant nearness of death by cold. The Valhallans learned to value the group over the individual and stoic perseverance over heroics, a mindset forged by generations of survival in a world that offered no comfort and no escape.
That resilience was tested to its limit when a massive Ork invasion descended upon Valhalla, threatening to overrun the ice world entirely. The war that followed was long and terrible, and the Valhallans triumphed not through brilliance but through sheer stubborn refusal to break, spending their own lives without flinching to grind the green tide down and reclaim their frozen home. That long ordeal is remembered in every regiment raised since, a lesson written in frost and sacrifice.
From that crucible came the Valhallan Ice Warriors, regiments of the Astra Militarum famed across the galaxy for holding the coldest, grimmest, most hopeless positions without complaint. The soldiers of Valhalla fight in disciplined, numberless ranks, enduring conditions that would shatter other troops and pressing forward whatever the cost in blood and frost. They fear neither the cold nor death itself, only the shame of failing the Emperor, and in the frozen theatres of war there are few defenders the Imperium would rather have at its side.