Citadel is short for the Granite Citadel, which is one of three places in
which 15k Armor can be obtained. The armorer, known as Hagen, will sell two
sets of 15k Armor for each class. Depending on your class, the armor you are
looking for might be at Marhan’s Grotto.

The Granite Citadel can be found in the Southern Shiverpeaks. If you go from
Copperhammer Mines and a little west then straight north, you will find the
Granite Citadel. Be prepared for a tough fight once you get near the outpost.

EXAMPLE: The 15k Platemail for Warriors at the Citadel is cool looking.