Evil Dwarves: When Aule's Children Served Morgoth | Tolkien Explained

A study of the Dwarves who fell. Aule engineered his children to endure the power of Melkor — stone-hard, stubborn, fast in enmity, incorruptible by any outside will. No Dwarf ever became a wraith. But that same hardness left them vulnerable to a different kind of fall: the love of a made thing turning into worship of it. Mim the Petty-dwarf led Morgoth orcs to Turin out of personal grievance. The Dwarves of Nogrod slew King Thingol in his treasury over the Nauglamir. The Seven Rings inflamed greed in seven Dwarf-lords without dominating them, breeding hoards and dragon-sickness from Thror to Thrain to Thorin. Four whole Houses beyond Rhun drifted into Sauron shadow in silence. Yet Azaghal, Belegost, and Dain prove the design held — most Dwarves chose otherwise, and Thorin confessed the pattern before he died.