Page 285 of Mercy Written in Blood

"No. Between two."

The diagram shifted. Human blood entered one network. Vampire blood entered the other. They did not mix directly. Energy passed across membranes drawn as thin geometric lines.

"The Takahara treated haemorrhagic illness by transferring regenerative force without exchanging blood," Renji said.

Akiko stared at him.

"That is impossible."

"No."

"You cannot separate regenerative response from vampire cells."

"We cannot."

Renji looked at the diagram.

"They could."

Haruki's gaze remained on the moving lines.

"What did that allow them to do?"

Renji read the annotations.

"Accelerate clotting. Repair vascular damage. Stabilise organ failure."

"In humans?"

"Yes."

"Without turning them?"

"Yes."

The room seemed to contract. Hemomancy was described in official vampire history as primitive blood manipulation — a dangerous art, unstable, predatory. Practitioners were said to control bodies through blood, create dependency and alter human minds. The Takahara massacre had been justified partly through allegations that they practised forbidden forms of it. Renji had believed those accounts. Not entirely. But enough to feel shame whenever the word appeared.

He lifted the second tablet. This one opened more quickly. A treatment protocol emerged — human and vampire physiciansstanding on opposite sides of a patient. The vampire did not feed. The human did not bleed. Each maintained one portion of the working. Neither could complete it alone.

Haruki saw the pattern.

"Everything requires both."

"Yes."

"Why?"

"Safety."

Renji followed the annotations.

"A vampire could provide regenerative force, but a human physician controlled the rate through the patient's pulse. If the vampire attempted to take control, the circuit collapsed."

"And if the human tried to harm the vampire?"

"The circuit collapsed."

Haruki looked towards the entrance.