Steel Sword (Mastercrafted): Abandoned In Boxholm

Travel to the abandoned settlement of Boxholm in the upper central area of Ard Skellig. At the signpost, head east toward a ruined water tower with two spires. The wolf sign is behind some low bushes on the stone wall, to the right of the towers.

More importantly, the chest is up the sunken stone steps to the east, right of the two watchtowers, up and over the wall, and then a short walk left (north) to a ruined wall surrounded by bracken.