Heading from south toward this location you can notice the shard inside what looks like an awesome tree house. In order to reach it you should proceed toward the center of Old Town Cavern. This is a crafting camp. There are cellar doors at the center of a camp. You can craft 3 piece “Night Mother’s Gaze” set here. Three set items give critical attacks and also reduce the targets armor by 20% for 5 seconds.
Near the cellar entrance to crafting stations is a path that leads toward the collectible. There are couple of level 37 Skeevers defending it.
“treehouse” like structure holds the shard.
Path that leads you to the collectible is near the cellar of Old Town Cavern.
Sand Kingdom Moons - Super Mario Odyssey Power Moons