The Stout-axes were a clan of Thrall-dwarves from Mordor also once known as "Drása's folk".Most likely descendants of the Ironfists and Stiffbeards, they had been brought to ruin by their desire for the Ring once granted to them by Sauron and the treason of the Mornaugrim.The Stoutaxes worked the dangerous engines of Udûn and beneath Barad-Dûr itself.After the War of the Ring the tribe split into two rival factions, one chose to seek aid and shelter with Dúrin's folk at Erebor while the other renamed themselves the "Firehorns" and followed their King into the Underdeeps beneath Barad-dûr on a desparate crusade to find their ancient ring.
Notes
The Stout-Axes of LOTRO were created as a possible stand-in for one of the four canonical tribes of the Eastern Dwarves.Their supposed relation to the Zhelrúka would suggest the Stiffbeards, however the Zhelrúka stronger resemble the Stiffbeards supposed look, also the Stoutaxes are stated to be not used to cold nothern climates.