Silmarillion, Ents vs Dwarves
The chapter “Of the Ruin of Doriath” in the Silmarillion is epic. Thingol, high king of the Sindar elves, ask the dwarves of Ered Lindon (the Blue Mountains) to set his Silmaril jewel into the famed Dwarven necklace the Nauglamir. After the necklace is complete the Dwarves covet the work, and quarrel with King Thingol, who perceives their greed and insults them. In a rage the Dwarves slay Thingol and keep the Nauglamir and the Silmiral set within. The elves avenge the slaying of their king but a couple of dwarves escape to enflame the Dwarves of the Blue Mountains who return to Doriath and emerge victorious versus the Elves in “The Battle of the Thousand Caves.” The Dwarves on returning home with their plunder are ambushed by Beren (of Beren and Luthien fame of course) and a host of Green-elves of Ossiriand. The Dwarves try and escape the ambush but are met by the Shepards of the Trees, and the Ents make sure no Dwarves make it home.
I really love this chapter. Elves fighting Dwarves, and Ents banding together with Elves (and a man) in retribution for greed and murder. Epic and cinematic, and interesting to imagine.