The final ingredient: Blood of an immortal vampire
They say human blood sustains life, but the blood of an immortal vampire is life itself. Highly addictive, the main source of the various supernatural abilities possessed by these creatures and which serves as their literal life essence. It is useless to other vampires who possess the same blood in their veins, but is life to the humans.
For centuries, the vampire community has succeeded in keeping this precious gift a secret to the humans, else they try to start hunting vampires for their blood. The sacred blood that heals and turns the natural to the super, blesses us with healing and gives humans a second life.
The blood of a vampire gives the essence to immortals,
Humans who drink it can escape the death portals.
Humans who drink it can form a bond with the blood giver
But do not drink too much, else your human blood will wither.
This precious blood that flows through the strong immortal veins,