Hammers of Sigmar: Age of Sigmar: Realmgate Wars, Book 4 (Unabridged‪)‬

Amongst all of the Stormhosts, none are more vaunted than the Hammers of Sigmar. Forged first upon the Anvil of the Apotheosis, their Warrior Chambers are exemplars of Sigmar's glory.

In the shadow of the Nomad City, the mettle of the Stormbound is tested against the hordes of Khorne in the battle to sanctify the Crucible of Blood, a gateway to Chaos and madness. Within the ranks of the Stormcast Eternals, there is one who is greater than all others. He is the Celestant-Prime, Sigmar's Storm made manifest.

For centuries he slumbered, until the great hammer of Sigmar, Ghal Maraz, was returned and he rose again. But a warrior born must still be tempered, and so unto the swamps of Krahl does Sigmar cast his scion to destroy a powerful creature called the Prismatic King.