In Assassin's Creed Valhalla: Wrath of the Druids you can acquire equipment items (gear) not only during quests, but also from special chests that contain interesting items. The DLC introduced new weapons. Below, we described the location of the Cu Chulainn Shield
Location: You will find this weapon on the southern part of the map, near the River Liffey.
To get to the chest, you must go under the waterfall.
To get to this chest you need 5 Ui Neill Artifacts. We have described them in detail in our guide on the page - Ui Neill's artifact - entire collection.