The Cemetery Shades are black beings that appear in dungeons around the Lands Between. These beings wield a weapon called the Mantis Blade that has the ability to double its size, making these enemies harder to dodge. They also possess the ability to paralyze you for a brief moment so they can come in and strike. A Cemetery Shade will quickly end your playthrough if you aren’t careful. Here is where you can find all of the Cemetery Shade bosses in Elden Ring.
The first of the Cemetery Shade bosses you will probably come across is down in the Weeping Peninsula. This is the area to the south of Limgrave on the other side of the Bridge of Sacrifice. After reaching the peninsula, head south until the road splits and follow the path west. You will find the Tombsward Catacombs near the road in the center of the peninsula. The boss is located in the dungeon and will drop summoning ashes for Lhutel the Headless when defeated.
The next Cemetery Shade is located in Lirunia. This is the land to the north of Limgrave that is on the other side of Stormveil Castle. The boss here is located at the end of the Black Knife Catacomb. There is also a Black Knife Assassin boss in these catacombs, but the bosses are separate. To reach these catacombs, head north in Liurnia and head east to where the land meets the lake in the center of the region. Follow the path north along the cliffside and it will take you to multiple cliffs with gravestones sticking out of them. This is where the catacombs are. Once you defeat the boss, it will drop the Twinsage Sorcerer Ashes.
The final Cemetery Shade can be found in the Caelid region to the east of Limgrave. This area is where things will start to get tough in the game so keep on your guard. After reaching Caelid, head southeast toward the Impassable Greatbridge. Follow the southern cliffside and you will find the entrance to the catacombs next to a tree with a large crow waiting to attack. For defeating the Cemetery Shade in this dungeon, you will get the Kindred of Rot Ashes.