Said to be the greatest fortress ever built, the Dros was originally commissioned by the great Earl of Bronze Egel in 1073, upon the counsel of his advisor Dardalion, Abbot of Swords and founder of the Thirty. It was mocked by some as "Egel's Folly".
During the Siege of Dros Delnoch in 1226, the fortress served as the battleground for a desperate struggle between the Drenai defenders and the Nadir horde of Ulric Wolfshead, the first Nadir Uniter. Ulric barely failed to take the fortress and it remained unconquered.
The fortress was however conquered a century later by the second Nadir Uniter, Tenaka Khan, who renamed it Castle Tenaka.
Each of the six walls had a name carved into it in the Elder tongue, mirroring the emotions of the defenders at each successive retreat during a siege. From outermost to innermost the walls were named as follows: