Shade remains are obtained by killing shades in Mort'ton and in the Mort'ton dungeon. A minimum of a Bronze key is required to enter Mort'ton dungeon (obtainable by killing a Loar shade in Mort'ton and cremating the remains per the instructions below). Deeper into the dungeon (access determined by key color), higher levels of shades are found. Cremating higher level shades (using higher level pyre logs) yields higher level keys, which get you further into the dungeon. The key hierarchy is Bronze, Steel, Black, and Silver. The keys also open color-coded chests, and the higher level keys/chests yield better loot, including a greater chance of obtaining Fine cloth (a rare item used to make Splitbark armour).