|“||Crafting Material. Found most often in Shadow Arenas and Shadow Dungeons.||”|
— Item Tooltip
Shadow Shards are key crafting materials used to make Shadow Cache from the Shadowy Market and several shadow themed mounts (Appeased Dream Gobbler and Erimatra, Scourge of the Everdark). At the end of "Normal" leveled Shadow Tower Shadow Pinnacles (Boss Rooms) players can obtain several shards from the Shadow Tower Vault. Going to higher difficulties will give Shadow Caches rather than shards.
On Mondays players gain double (triple as Patron) more shards from Shadow Towers.