There are 3 different endings in Bloodborne which become accessible after defeating Mergo's Wet Nurse and they happen in the Hunter's Dream. This is noticeable thanks to the burning of the workshop and new dialogue of The Doll, which says "Good hunter, you have come... Dawn will soon break... This night, and this dream, will end. Gehrman awaits you, at the foot of the great tree. Go on, good hunter..." From this moment the player can either keep exploring Yharnam or access the graveyard zone of the Dream where Gehrman awaits The Hunter to inform him/her the contract made at the beggining of the game is done and he/she can die in the dream to finish the hunt.
The Hunter can accept or refuse this offer, resulting in one ending or another.
After any of the three endings and the forthcoming credits, the game ends and the player will start a New Game +
Ending "Yharnam Sunrise"
In this ending, the Hunter accepts Gehrman's offer of release from the dream. The Hunter kneels before Gehrman, who rises from his wheelchair and executes the Hunter. The Hunter then wakes up in what appears to be Central Yharnam with the sun rising while a bell is rung in the distance, signifying that the night and the hunt is at an end for now.
Finally, The Doll is seen praying near a tombstone, most likely the player's, saying "Farewell, good hunter. May you find your worth in the waking world.". Then the credits roll.
Ending "Honoring Wishes"
This ending happens if the player refuses Gehrman's proposition and hasn't yet consumed three Thirds of Umbilical Cord. In this ending, the Hunter refuses Gehrman's offer of release, prompting Gehrman to rise from his wheelchair and ready his weapons, in order to force the Hunter to accept their fate.
The Hunter kills Gehrman, prompting the Moon Presence to appear. As the Hunter approaches the creature, it grabs them. Just as it did with Gehrman, the Moon Presence enslaves the Hunter, who is now forced to carry out the same role as Gehrman did. Some time later, the Doll is seen pushing the Hunter around the workshop in Gehrman's old wheelchair as the moon turns red and the hunt begins anew.
Ending "Childhood's Beginning"
This ending is obtained by defeating Gehrman, as in the "Honoring Wishes" ending, and having used at least three Thirds of Umbilical Cord before overcoming Gehrman. After defeating Gehrman, the mysterious Moon Presence descends from on high. As the Hunter approaches it, it grabs them, intending to subvert the Hunter to its will. The Hunter, with the power granted to them by consuming the Umbilical Cords, is able to resist the Moon Presence's influence, prompting it to attack.
The Hunter succeeds in defeating the Moon Presence, and ascends into an infant Great One, that is found and cared for by the Doll.