These are used in task Recycled Arms.. Part of series for putting together a nice augment.. like AC 20 HP 72 +16 Diease +16 poision.. This particular task is given by Brother Veras in Camp Valor. go to SW part of zone .. there is a ruined town with lots of undead elves .. in the town are 5 or so barrels.. Open barrels and remove item.. Task takes 15.. Task also gives Camp Valor faction..
Actually, there are 15 barrels with the Elven Armaments in them. Only takes a few minutes to loot them if you are wearing "Eye of Kirathas" to modify the faction with the village. The mask is bought from "a mysterious strange".