The Warmace of Shirvallah

The Warmace of Shirvallah unlocks the Zandalar Champion appearance for the Doomhammer (artifact) artifact.

Source
This item is dropped by the following world bosses in the Broken Isles:
 * Flotsam in Highmountain
 * Humongris in Val'sharah
 * Levantus in Azsuna

It is also dropped by Helya in Trial of Valor.

Trivia

 * While the warmace is named after Shirvallah, the ornaments on the mace itself is representative to that of direhorns.