Cemetery Shades are black entities that appear in dungeons around Lands Between. These beings wield a weapon called the Mantis Blade that can double in size, making it more difficult to dodge this enemy. They also have the ability to temporarily paralyze you so they can come in and attack you. Graveyard Shade will end your play quickly if you are not careful. Here you can find all Cemetery Shade bosses in the Elden Ring.
The first Cemetery Shade boss you will encounter is located on the Weeping Peninsula. The area south of Limgrave across from the Bridge of Sacrifice. After reaching the peninsula, go south until the road splits, then follow the road west. Near the road in the middle of the peninsula is the Tombsward Catacombs. The boss is in the dungeon and when you defeat Lhutel, it will drop a summon material for the headless rutel.
The next cemetery shade is in Lirunia. A land north of Rimgrave opposite Stormvale Castle. The boss here is at the end of the Black Sword Catacombs. There is also a Black Knife Assassin boss in this catacombs, but the boss is separate. To get to this catacombs, head north from Liurnia and then east, where the land meets the lake in the center of the area. Follow the road north along the cliffs to several cliffs with tombstones sticking out. This is where the catacombs are located. Twinsage Sorcerer Ashes drop upon defeating the boss.
The last cemetery shade can be found in the Caelid area east of Limgrave. This area is where things start to get difficult in the game, so stay vigilant. After reaching Caelid, head southeast towards the impassable bridge. Follow the southern cliff to the entrance to the catacombs next to a tree with large crows waiting to attack. You can get Kindred of Rot Ashes by killing Cemetery Shade in this dungeon.