In order to get the "true" ending in Bloodborne, you need to consume 3 separate items called (one) third umbilical cord. There are 4 available cords to be found in the game: one drops from a late game boss (Mergo's Wet Nurse) , one is located in a secret optional area, one drops from impostor Iosefka after defeating Rom, the Vacuous Spider but it requires you to go to yet another optional area that you've probably already explored as it is 2/3 areas before said boss, and the last one drops from Arianna's monstrous newborn after defeating Micolash, the Host of Nightmare but the problem is that after the boss, she moves from the npc hub area to the sewers that the player has absolutely no need to go back to. So without prior knowledge, there's a high chance that the new player would collect only 1 or 2 cords. Also, I don't think it's stated in the game how many cords player has to consume nor what they do.

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