Biology of the Revenant

Revenant: n. 1.  One that returns after a lengthy absence. 2. One who returns after death. 3. Vampire. [French, from present participle of revenir, to return]

[Revenant Conversion | Revenant Anatomy | Continuum of Revenant Evolution | Non-human Revenants]

Revenant Conversion

A human is converted – that is “brought back” – by moderate to severe exsanguination, combined with ingestion of revenant blood. The amount of revenant blood required varies – anywhere from a half-ounce from a blood-addict to a pint from a high-functioning revenant. Simply drinking revenant blood without the accompanying loss of host blood does NOT lead to conversion, though cases of a conversation following a relatively mild blood loss of only 2 to 3 pints has been recorded. 

Following ingestion of revenant blood, the host develops a severe blood poisoning as the revenant blood cells begin attacking healthy cells. Depending on the degree of exsanguination, cardiac death to the human convert follows within minutes or hours (rarely, this period of active infection can last several days). Brain death does not occur, however, and the convert remains in a form of suspended animation as the conversion process modifies his anatomy and bio-chemistry. This incubation period lasts anywhere from 2 to 24 hours.

The newly converted revenant wakes up hungry. The first meal of blood often sets the feeding pattern to follow. A newborn revenant who drinks human blood immediately will find it very hard to adapt to a more varied diet.

The vast majority revenants are consciously converted by their mentor (though the converted is often himself unwilling). A mentor will often stay with the newly converted and help him adjust to realities of being a revenant. In some cases, mentor and disciple will form a long-lasting partnership. More often, the two part ways after a period spanning months to years. Revenants are by and large solitary beings. 

In rarer cases, a mentor does not remain with the newly coverted. The long-term survival rates of orphaned revenants are very low.

Revenant Anatomy


The revenant’s basic anatomy is nearly identical to a living humans. Significant exceptions are as follows.

Nervous system:

The revenant nervous system is very similar to its human counterpart. The major difference is a heightening of senses. In particular, revenants have a highly developed sense of smell. Revenants can also see a wider range of the visual spectrum. Their infrared – or “night” – vision is very sharp, allowing them to see in what humans perceive as complete darkness. 

The revenant brain can regenerate even after significant trauma, albeit with temporary loss of higher cognitive function. Severe brain damage to revenants often erases significant portions of their human memories, in effect “resetting” them on a purely instinctive level.

Circulatory system:

Contrary to popular belief, a revenant does have heartbeat. The revenant circulatory system is extremely efficient, distributing fresh blood to the body with a minimum of effort. The resting heart-rate of the average revenant can be anywhere between 10 and 20 beats per minute, and the revenant pulse is so faint as to be undetectable to a layman. 

Revenants are considered “cold-blooded” organisms because they cannot internally regulate their own body temperature. The revenant controls his body temperature primarily through feeding on fresh blood (artificially heated blood is an acceptable substitute). Like his human counterpart’s, the revenant circulatory system will divert blood to the body core in order to preserve optimum body temperature. Thus revenants who have not fed recently exhibit a cooling of the skin, beginning in the extremities. Drinking hot liquids and seeking out warm air provides a certain measure of temporary relief.

Digestive system:

The digestive system undergoes a chemical transformation during conversion process, adapting it to digest and absorb the nutrients and thermal energy found in human blood. The revenant’s gastrointestinal tract is extremely efficient, and a revenant subsisting entirely on human blood produces no waste, and thus has no need to defecate. The intestines’ ability to absorb solid food is severely compromised, however, and a revenant attempting to “pass” for human will have to consume up to three times the calories a human does in order to avoid rapid weight loss. 

A revenant seeking to expand his diet to solid foods should proceed with caution. Significant intestinal distress will result during the “re-training” process. Of solid foods, meat and dairy products are best tolerated by the revenant digestive system.

A note about garlic: Due to its supposed mystical properties, garlic has often been considered a deterrent to revenants. While many revenants do react negatively to garlic, it is more a distaste of its strong aroma than a genuine aversion. Trying to ward off a vampire with raw garlic is more likely to annoy (or enrage) the subject than deter him.

Respiratory system:

Revenants do not require oxygen. Their respiratory system is used only to harvest air for speaking. Many higher-functioning revenants do continue to breathe, either out of a conscious desire to appear human, or simply out of reflexive habit. Such breathing does not continue into unconsciousness, as a revenant has no automatic respiration. 

Regenerative properties and weaknesses:

A revenant’s ability to heal is directly linked to his blood consumption. Human blood is the best “medicine” but significant consumption of any blood – even dead blood, will trigger the self-healing reaction. Revenants can be killed, but only with difficulty. Even direct bullet wounds to the head may not be fatal. Revenants cannot regenerate amputated limbs, however, and significant damage to the heart is invariably fatal.

Revenants are most vulnerable to sunlight – specifically ultraviolet rays. Direct contact with UV rays cause third-degree burns to the skin, and prolonged exposure will eventually lead to fatal damage to the underlying tissue and organs. Even indirect sunlight is known to cause varying degrees of eye irritation (included temporary blindness), and severe headaches. 

The most successful methods of revenant execution include:


Continuum of revenant evolution

While revenants are best adapted to hunt and consume humans, they need not consume human blood to survive. Human blood is addictive to a revenant, however, and increased consumption will cause a revenant to evolve further and further from his original human form.

Class 1: “High-Functioning”

Though human blood is the preferred food source of the revenant, a strong-willed revenant can learn to subsist on non-human blood. As animal blood is less nutritious, more must be consumed (on average 1-2 quarts a night) in order to remain healthy. 

The high-functioning revenant is so named because he is best able to integrate in human society. While there are still notable differences between a revenant and a healthy human, they are often subtle enough that a cunning revenant can escape detection by the common man. Identifying signs of a high-functioning revenant are as follows.

A skilled high-functioning revenant has a fictional medical history prepared, and rigorously avoids physicians. He is considered an “eccentric character” by his neighbors, but is usually tolerated and at times even respected, especially in bohemian circles. Due to the lack of aging, a well-prepared revenant will move towns every 5-10 years, and reinvent his identity as needed to allay suspicion.

Class 2: “Low-Functioning”

A revenant who feeds on human blood regularly (3-4 times a week), even if he limits to non-lethal feedings, will begin to exhibit classic signs of vampirism. 

A low-functioning revenant is still able to assimilate on the margins of human society, although his symptoms and behavior make him a pariah and an object of suspicion to his neighbors. In traditional and rural societies, it may only be a matter of time before the revenant is properly identified. In the urban environment, the low-functioning revenant will frequently be misidentified as suffering from advanced lupus, tertiary syphilis, cirrhosis, or porphyria. 

At this stage, the revenant finds himself at a crossroads. If he is properly educated in revenant biology, he can make a choice to reduce his intake of human blood in order to preserve a human appearance and reduce his vulnerability to sunlight. Such a course of action, however, requires a willpower most low-functioning revenants no longer possess.

A low-functioning revenant who makes no effort to limit his consumption of human blood invariably succumbs to blood-addiction within months. 

Class 3: “Blood-addict”

Once a revenant begins to feed exclusively on human blood, his deterioration accelerates. Increasingly severe withdrawal symptoms – severe pain, nausea, anxiety – drive the revenant to increase his consumption, which increases his tolerance and feeds the addiction further. Body changes are marked:

At this stage the revenant cannot find acceptance in human society – nor does he want to, for he has come to regard humans solely as a food source. He begins to consciously reject human culture, and seeks solitude in the wilderness – often in caves or thick wooded areas where he can build a light-proof nest in which to sleep. 

A note about coffins: Very few revenants actually sleep in coffins. Higher functioning revenants have neither need nor desire, and while blood-addicts might scavenge a coffin or a light-proof box, they are very unlikely to consciously procure one.

Despite his increased strength and endurance, the blood-addict is the most vulnerable of all revenants. With the more severe allergy to sunlight and no “cover” to hide behind, he must take great care to keep at a distance from humans, and to preserve the integrity of his nest. Blood-addicts often roam across a wide territory, often keeping several different nests within striking distance of different settlements. As dementia increases with advanced blood addiction, many revenants become careless in their hunts, inviting detection and persecution. The rapid urbanization in many areas of Europe and North America is a contributing factor in the downfall of many blood-addicts.

Non-human revenants

Non-human revenants are a rare subset of revenants, usually created by accident – a dog or wolf attacked by a revenant will fight back, inflicting damage and swallowing enough blood to affect the transformation. Just like an un-mentored human revenant, most animal revenants will not survive their first year. 

There have been isolated incidents of higher-functioning revenants intentionally converting a beloved pet. Canine revenants display very mild photosensitivity, and with strict training, can adapt to a blood-rich but not blood-exclusive diet. Caution must be exercised, as impulse control and increased aggression will remain a critical focus for the first year. Successes with feline revenants are much rarer.

There is no known case of a herbivore being “brought back.”


Jane Senese 2013.