Entity: Sanguimancer

May contain spoilers from Shades of Blood

Source Pathfinder #213: Thirst for Blood pg. 83

There’s a balance in blood. The arteries send surges of the fresh, life-giving liquid to the furthest reaches of the body, even as the veins return spent blood to be renewed. Healthy blood contains the essences of life and energy, while unhealthy blood might be anemic or even laden with disease. Within this duality of blood is great power—to infuse energy, health, and life, or to expunge it just as quickly.

Some individuals are sensitive to the power within blood, and in time might even begin to control it. This practice is known by magical scholars as sanguimancy to distinguish it from a sorcerer’s magical bloodline, though most people are ignorant of the distinction and use the same term—blood magic—for both. Sanguimancy is a strange and lonely path. Those who practice it are few in number, and when they do come into contact with others, people often react to them with caution, if not outright revulsion. Consequently, few actively seek out these bloody powers. Those with ties to blood, be it vampires and their associates, practitioners of bloody rites—such as worshippers of Camazotz—or even specialists in medicine can all find themselves drawn to sanguimancy.

While its effects are undeniably magical, sanguimancy falls outside the established norms of spellcasting. Casters combine spells with sanguimancy to create powerful synergies, while warriors appreciate being able to wield their abilities even after their peers’ spells have run dry. The most powerful sanguimancers can wield the energies contained within blood to shield themselves from harm, cause internal bleeding, and even unleash a barrage of razor-sharp needles of blood.

Blood sensitivity is uncommon but found in diverse places. It’s difficult to tell if someone is blood sensitive without them admitting to it or overtly manifesting their powers in public. As a result, estimates of how many members of a population are blood sensitive tend to be accurate only if sanguimancy is tolerated. Another tradition of blood magic, hemotheurgy, has many similarities to sanguimancy but carries a far different effect on its practitioners. The leech‑covered bloatmages of Kaer Maga practice this self-destructive magic, overriding their bodies’ fail-safes to produce more blood than their bodies need in order to enhance their magic.

The precise manner in which blood sensitivity comes about remains poorly understood, even among the magical scholars who have rigorously studied its existence. Most agree that exposure to fresh blood is a key factor in manifesting the attunement. Some speculate that repeated exposure from a young age is necessary, while others surmise a single incident might be all that’s required, provided that such an event occurs while in a state of extraordinarily heightened emotion. And, of course, some believe that blood sensitivity could be a divinely preordained gift (or curse), an affinity you’re born with, or a simple matter of luck. As of yet, no one has been able to reliably induce a test subject with the power of sanguimancy, and most experiments attempting to do so are considered evil.