Behind that army was a passage which led to a large arena lined with 50 or so skeleton archers. Too bad for them I was a better sniper and they all died without ever detecting me. Then came a lair of charrus, followed by an army of Falmer led by dragon priests. The carnage was beautiful.
Die you mutated elves!
Finally I found the lair of the boss guy: Lord Garnad. His chamber was full of things that hurt a lot! Draugr amazon archers, dragon priests, whirly blade traps... I still out-potioned them all. Even Garnad himself who I happily executed while he begged for his life. He put up a decent fight though for someone being hit by a 900+ damage weapon. You didn't think I'd leave that behind in the bone dragon's chamber did you? :P
Dead like the dog he is.
Anyway, the final key was in a chest behind Garnad, and that led to a reward in the form of an Oblivion Sword and an Oblivion Crosier Staff. Pretty cool! The nearby exit put me at the very base of the floating mountain that happened to overlook a deep lake. I took the fastest way down. :)
Try this in real and it would probably be fatal.