From Tolkien Gateway
"Stout-axe" is a concept which has only appeared in an adaptation of the works of J.R.R. Tolkien.

The Stout-axes or the Khirvísa are a part of Drása's Folk, a House of the Dwarves created for The Lord of the Rings Online game by Standing Stone Games.

When they were lured into Mordor by their desire for their Ring of Power, they were eventually enslaved and lost to history. During the War of the Ring, they were under the command of the Black Númenórean Zôreth. Their king Váskmun Greytooth was brought to Barad-dûr, where he was forced to wear Manthríf until he could no longer endure it. After the defeat of Sauron they called themselves the Firehorns and, according to the game, they became free and many joined in the various endeavors of the other Free Peoples of Middle-earth.