What NPCs can you permanently kill in Bloodborne, and what are the implications?

Solution 1:

You do not have any direct consequences when killing an NPC besides that this killed NPCs will not help you in the combat anymore :P

When you kill an NPCs you also dont get a punishment of any kind. Other NPCs will think that they got killed by a enemy, even then when they have full health and you kill them directly in front of the other NPC.

The following reddit post contains a discussion on how to get the most out of NPCs. Warning! The Reddit post contains spoiler! Click here if you are aware of potential spoilers

_{Image 1 - A friendly NPC called Plain Doll. You can find her at Hunter's Dream}