As soon as you defeat the Wet Nurse and travel back to the hunter’s Dream, you will find the Workshop in the Hunter’s Dream on fire. When you speak to the Doll, she will tell you that Gehrman is waiting for you by the Great Old Tree.
Note: Before going to where Gehrman is, remember that the game may recognize that you are already ready to end the game, thus making it no longer possible to explore optional or hidden maps or defeat optional bosses.
When you approach Gehrman, he will tell you that the hunt is finally over. He will then offer you “mercy” and “kindness” by giving you the death you deserve in order to wake up in the real world and not remember anything of the nightmare that has passed.
The game’s ending will largely vary on the choice you will make.