Ballora, Funtime Foxy, Baby (Series 1) Foxy, Cupcake, Chica (Series 2) Freddy, Bonnie, Balloon Boy (Series 3) Nightmare Bonnie, Nightmare Chica, Nightmare Freddy (Series 4) ...

For the Essence of Obscurity, you need the Withered Plumes item, located in the Circle of Bones. Here's how to find your way to the location, and where the item is hidden when you get there.