Guide:
Southeastern Deshaan, south of Coiled Path Landing (eye icon), south-southeast of Ghost Snake Vale Wayshrine, south-east of Taleon’s Crag (public dungeon).
Start at Coiled Path Landing, and go south. You will reach a river going outside of the map. Just follow it until you see a small island in the middle of the river. The skyshard is located on this small island, in a wooden crate, next to a tree and a big stone. The “Ebony Blade History” lorebook is next to the wooden crate too.