Old Blood: What "Fear the Old Blood" Means in Bloodborne

The old blood is the substance at the root of Bloodborne's story: a "holy medium" that scholars of Byrgenwerth found deep in the tomb of the gods beneath Yharnam. The Healing Church was founded on it, Yharnam's blood ministration comes from it, and the warning "fear the old blood" is one of the most repeated lines in the game. What the blood actually is, the game never says outright. (Bloodborne)

What does the game say the old blood is?#

The most direct account comes from Alfred, the Executioner hunter. Byrgenwerth is an old place of learning, he says, and the tomb of the gods carved out below Yharnam should be familiar to every hunter. A group of young Byrgenwerth scholars discovered a holy medium deep within the tomb, which led to the founding of the Healing Church and to blood healing. Everything sacred in Yharnam, he says, can be traced back to Byrgenwerth. (Bloodborne)

Alfred also says the holy medium of blood healing is venerated in the main cathedral. The Grand Cathedral is where the player finds a beast-like skull on the altar and, touching it, sees a vision of Willem and Laurence. (Bloodborne)

"Fear the old blood"#

In that vision, Laurence comes to bid Willem farewell and tells him, "I will not forget our adage." Willem recites it: "We are born of the blood, made men by the blood, undone by the blood. Our eyes are yet to open." Then both men say "Fear the old blood" together. (Bloodborne)

The phrase turns up across the game. A note in Cathedral Ward says a watchman of Byrgenwerth guards a gate with a password, "the sacred adage of the Grand Cathedral". The password to the Forbidden Woods gate is "fear the old blood". A note inside the cathedral tells the faithful to inscribe Master Laurence's adage upon their flesh. When Gehrman kills the player in the Yharnam Sunrise ending, his last words are "Fear the blood." (Bloodborne)

The blood in Church teaching#

The Church took the opposite lesson from Willem. Vicar Amelia's prayer says: "Seek the old blood. Let us pray, let us wish to partake in communion. Let us partake in communion and feast upon the old blood." The Communion rune says blood ministration is the pursuit of communion. (Bloodborne)

The Blood Vial explains the habit that followed. Once someone's blood has been ministered, each new infusion recalls the first and is all the more invigorating, and so most Yharnamites are heavy users of blood. The Sedative notes that arcane scholars calm their nerves with blood, which often leads to reliance on ministration. (Bloodborne)

What else does the game say about blood?#

Several item descriptions link blood to the Great Ones without naming the old blood:

• The Formless Oedon rune says oozing blood, "human or no", is a medium of the highest grade and the essence of the formless Great One Oedon, who seeks it along with his "inadvertent worshippers". (Bloodborne)
• Arianna's One Third of Umbilical Cord says Oedon too yearns for a surrogate child, and that "it was corrupted blood that began this eldritch liaison". (Bloodborne)
• The Blood of Adeline says the Church treated Blood Saints to produce worthy blood. (Bloodborne: The Old Hunters)
• Alfred says a Byrgenwerth scholar took "forbidden blood" to Cainhurst Castle, where the first Vilebloods were born. (Bloodborne)

Is the old blood the blood of a Great One?#

The most common reading is yes: the scholars found a Great One, or its remains, in the tomb of the gods, and its blood became the Church's medicine. The evidence is indirect. The blood came from the "tomb of the gods". The Oedon runes call blood a medium of the highest grade. The Church's chapel carries Oedon's name. And the Choir later found Ebrietas in the same underground tombs. None of this is a direct statement. (Bloodborne)

The second big reading is that the old blood caused the scourge of beasts. Laurence's Skull says he became the first cleric beast. The Sword Hunter Badge says many Church hunters were clerics, and clerics turned into the most hideous beasts. A Lecture Building note says Willem was right that evolution without courage would ruin the race. Put together, that reads as the blood turning its users into beasts, but the game leaves the final link unspoken. (Bloodborne; Bloodborne: The Old Hunters)