There is a quest to combine the dragon priest's masks. I have all the masks but haven't received the quest yet. I was told you get it after you get all the masks – I have been waiting for a long time, is it a bug?
Can’t get quest for combining dragon priest masks
the-elder-scrolls-v-skyrim
Best Answer
That quest is unmarked and never appears in your journal. Find the wooden mask outside Labyrinthian and put it on, then you'll need to put the 8 masks on a rack to receive the 9th.