While searching for this collectible you are going to end up on an island with a circular crossroad. Following the main road that goes east of this island you can notice the wooden bridge. This wooden bridge connects the island with southern Greenshade. Just bellow it is the skyshard. Further more to east you can find Heluin NPC. Heluin gives the quest “Mist and Shadow“. This quest is part of a nearby POI Shademist Moors objective.
Sand Kingdom Moons - Super Mario Odyssey Power Moons