What is covered in NPC Quests (Comprehensive) for Bloodborne?

Bloodborne's world is rich with cryptic lore and hidden narratives, often unveiled through the various non-player characters (NPCs) you encounter.

How do you complete NPC Quests (Comprehensive) in Bloodborne?

Bloodborne's world is rich with cryptic lore and hidden narratives, often unveiled through the various non-player characters (NPCs) you encounter.