The Old Blood is a term mentioned in Bloodborne.
The first experiment must have had mixed results as Master Willem, provost of the school, feared it and took the phrase "Fear the Old Blood" as his mantra.
However, Laurence, one of the scholars, saw the potential usage of the blood and departed from the school, forming the Healing Church where he studied the blood and spread it to the public as miraculous treatment, with the promise the sacred blood can cure any disease. However, misuse of the Old Blood is theorized to be the primary reason for the outbreak of the Beastly Scourge which plagues Yharnam.
The Old Blood is never actually seen by the player, but is instead mentioned throughout the game.
- He refers to it as a ”Holy medium”.
- "We are born of the blood, made men by the blood, undone by the blood. Our eyes are yet to open. Fear the Old Blood".
- "Fear the Old Blood".