In Assassin's Creed Valhalla: Wrath of the Druids, you can come across the Ui Neill Artifact, one of the collectible items. On this page of our guide, you will learn where to find masks and how to reach them. It will make it easier for you to max out the Connacht region.
You'll find the mask just south of Rea Lake.
To get to the Artifact, you must destroy the cluttered passage. You will do this with the right arrows or jugs of oil.
Once you are inside, run to the very end, then jump into the hole in the ground, and pick up the mask - it lies on the left.