Know Your LotRO Lore: Speak, Friend and Enter

The creation of the West Gate, also known as Durin's Door or Hollin's Gate, was essential in the friendship between the Dwarves and Elves. It was designed by Celebrimbor, the Lord of Eregion at that time, and built by the Dwarven master craftsman Narvi. It was the only other way into, or out of, Khazad-dûm.

On the eastern gate, an important defensive feature was built just inside the caves to ward off any attacks from enemies. This structure is known as Durin's Bridge, a slender stone bridge that spans fifty feet long over a "chasm of indeterminate depth." This bridge was built to only accommodate one soldier at a time, allowing archers to focus their firepower and prevent anyone from crossing.

In subsequent wars with the Elves, Sauron's forces were easily defeated from behind their rear flanks as the Dwarves emerged just long enough to battle, then retreat back into the West Gate. This wedged a burning hatred for the Dwarves into Sauron who dedicated much of his energy to driving them out of the mines once and for all.