The New York Times found the remains of a suspected child revenant. In 17th century Europe, the dead were thought to rise again and bedevil the living. Now researchers in Poland have found the remains of a suspected child revenant. Buried face down, with a padlock by its foot, the 400-year-old corpse was locked to its grave. The original word was derived from the Latin ‘revenans’. Revenant is a French word meaning “returning” which is used by folklorists as being the equivalent of “ghost”. There is some debate about origins:   some maintain that vampires derive from Eastern European folklore and revenants derive from Western European folklore, and most accept that “revenant” is a generic term for the undead.
Augustin Calmet conducted extensive research on the topic in his work entitled Traité sur les apparitions des esprits et sur les vampires ou les revenans de Hongrie, de Moravie, &c. 1751. Calmet related the rumors of men at the time, comparing the ideas of the Greek and Egyptian ancients and notes an old belief that magic could not only cause death but also evoke the souls of the deceased as well.  He also described belief in sorcerers who sucked the blood of victims and compares instances of revenants mentioned in the 12th century in England and Denmark as similar to those of Hungary; but, he said, “in no history do we read anything so usual or so pronounced, as what is related to us of the vampires of Poland, Hungary, and Moravia.”
A possible precursor of the revenant legend appears in Norse mythology, called the draugr or aptrgangr [literally “again-walker”]. Stories involving the draugr often involve confrontations with the creature. The draugr resisted intruders to its burial mound and was often immune to conventional weapons, which rendered the destruction of its body a dangerous affair to be undertaken only by individual heroes. In the folklore and ghost stories of Eastern Scandinavia, Finnish “dead-child beings” are described as revenants animated by restless spirits that could be laid to rest by performing baptism or other religious rites.
Revenant-like beings in Caribbean lore are often referred to as “the soucouyant” or “soucriant” in Dominica, Trinidadian, and Guadeloupean, folklore, also known as Ole-Higue or Loup-garou elsewhere in the Caribbean.

William of Newburgh:
Belief in souls returning from the dead was common in the 12th  century, and Historia by William of Newburgh [1136–1198 briefly recounted stories he heard about revenants, as do works by his contemporary, Walter Map. William wrote that stories of supposed revenants were a “warning to posterity” and so common that, “were I to write down all the instances of this kind which I have ascertained to have befallen in our times, the undertaking would be beyond measure laborious and troublesome… “It would not be easy to believe that the corpses of the dead should sally–I know not by what agency–from their graves, and should wander about to the terror or destruction of the living, and again return to the tomb, which of its own accord spontaneously opened to receive them, did not frequent examples, occurring in our own times, suffice to establish this fact, to the truth of which there is abundant testimony.
One story involves a man of “evil conduct” absconding from justice, who fled from York and made the “ill-fated choice” to get married. Becoming jealous of his wife, he hid in the rafters of his bedroom and caught her in an act of infidelity with a local young man, but then accidentally fell to the floor mortally wounding himself, and died a few days later.
Newburgh described the burial:

A Christian burial, indeed, he received, though unworthy of it; but it did not much benefit him: for issuing, by the handiwork of Satan, from his grave at night-time, and pursued by a pack of dogs with horrible barkings, he wandered through the courts and around the houses while all men made fast their doors, and did not dare to go abroad on any errand whatever from the beginning of the night until the sunrise, for fear of meeting and being beaten black and blue by this vagrant monster.
A number of the townspeople were killed by the monster and; so, thereupon snatching up a spade of but indifferent sharpness of edge, and hastening to the cemetery, they began to dig; and whilst they were thinking that they would have to dig to a greater depth, they suddenly, before much of the earth had been removed, laid bare the corpse, swollen to an enormous corpulence, with its countenance beyond measure turgid and suffused with blood; while the napkin in which it had been wrapped appeared nearly torn to pieces.
The young men, however, spurred on by wrath, feared not, and inflicted a wound upon the senseless carcass, out of which incontinently flowed such a stream of blood, that it might have been taken for a leech filled with the blood of many persons. Then, dragging it beyond the village, they speedily constructed a funeral pile; and upon one of them saying that the pestilential body would not burn unless its heart were torn out, the other laid open its side by repeated blows of the blunted spade, and, thrusting in his hand, dragged out the accursed heart. This being torn piecemeal, and the body now consigned to the flames…”

In another story Newburgh tells of a woman whose husband recently died. The husband revives from the dead and comes to visit her at night in her bedchamber and he ‘…not only terrified her on awaking, but nearly crushed her by the insupportable weight of his body.” This happened for three nights, and the revenant then repeated these nocturnal visits with other nearby family and neighbors and “…thus become a like serious nuisance,” eventually extending his walks in the broad daylight around the village. Eventually the problem was solved by the bishop of Lincoln who wrote a letter of absolution, upon which the man’s tomb was opened wherein it was seen his body was still there, the letter was placed on his chest, and the tomb sealed.

Abbot of Burton:
The English Abbot of Burton tells the story of two runaway peasants from about 1090 who died suddenly of unknown causes and were buried; but the very same day in which they were interred, they appeared at evening, while the sun was still up, carrying on their shoulders the wooden coffins in which they had been buried. The whole following night they walked through the paths and fields of the village, now in the shape of men carrying wooden coffins on their shoulders, now in the likeness of bears or dogs or other animals. They spoke to the other peasants, banging on the walls of their houses and shouting “Move quickly, move! Get going! Come!”
The villagers became sick and started dying; but eventually the bodies of the revenants were exhumed, their heads cut off, and their hearts removed, which ended the spread of the sickness.

Walter Map:
The chronicler Walter Map–a Welshman writing during the 12th century, tells of a “wicked man” in Hereford who revived from the dead and wandered the streets of his village at night calling out the names of those who would die of sickness within three days.
The response by bishop Gilbert Foliot was, “Dig up the body and cut off the head with a spade, sprinkle it with holy water and re-inter it.”
Although it was common knowledge that a revenant had to have been wicked or engaged in dark practices when they were living, no one was certain what caused certain wicked people (and not others) to reclaim their bodies after death while others seemed content to ‘rest in peace.’ Because of this, revenants were greatly feared. It was sometimes thought that the souls that created revenants were associated with a different type of evil than the average wrongdoer.
It seems to this writer, that those were difficult times to be alive… Just saying.

Werewolves that came back to haunt the living because they had not been properly killed. These revenant werewolves were said to roam battlefields and drink the blood of dead soldiers.
Well, what would you expect?
With the addition of other beings like werewolves and witches being able to come back as a revenant, it is understandable that these creatures posed such a threat to developing societies. It is generally agreed that the majority of revenants seem to be possessed by a need to come back and continue the wicked agenda they carried out during their days among the living, there are some accounts of revenants who seemed to be motivated by their violent and often tragic deaths.
Revenants who were not violent or wicked during their lifetime but experienced a tragic or gruesome death were known to come back in order to harass living relatives. It is noted, however, that some of these creatures had a much more sinister agenda. Some revenants who were not wicked in their lifetime are said to come back with the sole purpose of exacting revenge on their murderer. It is just common logic.
Although there seem to be many notable subcategories of revenants, the word for which the creature is named does not necessarily suggest a limitation for who or what could be considered a revenant. This word was used to describe the manner in which the monster manifested itself–as a reanimated corpse instead of a ghost or demonic entity. [To be technical about it.]. It is, however, important to note that there seem to be variations of revenants that allow for ghostly categorizing.
Revenants who appear in ghostly form are said to take the appearance of their corpse in most cases, though there are revenant ghosts who can be identified because they appear soon after a corpse has been buried and are uncommonly clean as well as surprisingly overdressed. Other than taking a ghostly form, these revenants tend to follow the same rules as others who have come back from the land of the dead.
At least, it is not particularly complicated.
Revenants are most commonly motivated by revenge and a restless spirit that feels its work in the land of the living has been left unfinished. Because of this, they will come back–either to haunt their living relatives, kill living people it holds a grudge against, or spread pestilence and disease. It is thought that their spirits are so dissatisfied that they are able to reanimate their bodies and dig their way out of the graves they were interred inside.
Obviously, a valid exposition of justice.
According to most legends, the revenant only holds power during the hours of the night. During the daylight hours, the creature is forced to retreat to its grave and sleep in a state of suspension that appeared similar to death but was not thought to actually be death. Although there are many convincing tales that surely should convince one of revenants who came back to life to hunt and haunt specific people, the majority of revenant stories consist of the creature seeking to spread death and disease among surviving members of their village.
Because of this, it has been hypothesized in later centuries that tales of the revenant came into being when people happened across a dead body that was in a stage of decomposition that was unfamiliar to the living at that point in time.
The science–simply put–is that revenants are most commonly motivated by revenge and a restless spirit that feels its work in the land of the living has been left unfinished. Because of this, they will come back – either to haunt their living relatives, kill living people it holds a grudge against, or spread pestilence and disease. Their spirits are so dissatisfied that they are able to reanimate their bodies and dig their way out of the graves they were interred inside. According to most supporters of the science, the revenant only holds power during the hours of the night. During the daylight hours, the creature is forced to retreat to its grave and sleep in a state of suspension that appeared similar to death but was not thought to actually be death.
The appearance of the revenant is often gruesome and difficult to behold. The revenant almost always appears in a body that has begun to decay but has not decomposed to the point that it can’t be recognized by those who knew it in life. Although a considerable number of witnesses claimed to have seen a revenant [as testified to in their writings], more often a revenant can be detected long before it comes into view because of its foul smell. This creature was said to smell of decomposition so vile that it could be identified from many yards distant.
Worse even than Durian fruit, apparently.
In addition to having BO, revenants have rotting teeth and sunken eyes that are thought to glow red. The fingernails of a revenant are regularly described as being bloody and jagged from the tremendous effort it took to dig themselves out of their graves. Its clothes are usually in a similar state of decay and destruction as they are often torn in the process of the corpse escaping from its coffin. Testimonies from witnesses describe revenants to be missing significant chunks of flesh revealing its bones and internal organs. Skin was often reported to hang from the lifeless limbs of the creature in shreds or to be missing altogether. Those who were unfortunate enough to have seen revenants in person also reported these creatures to have many maggots and worms inside their open wounds. These maggots and worms were also said to be found in other openings in the body such as the eyes and mouth.
Similar to being something like natural decomposition at about two to three weeks, depending on the temperature, it seems to me.
The bodies of these revenant creatures are uniformly described as being severely swollen with the blood of the victims they have murdered [which some modern people—who have not seen actual revenants—have thought was natural decomposition at about 10-20 days], although their reason for drinking blood is unknown. [One of those mysteries of science and religion, apparently.] As far as witnesses have been able to observe, a revenant does not need blood or any other sustenance to survive, unlike vampires, it is important to point out.

I chose to use a pseudonym for personal reasons. I’m a retired neurosurgeon living in a rural paradise and am at rest from the turbulent life of my profession. I lived in an era when resident trainees worked 120 hours a week–a form of bondage no longer permitted by law. I served as a Navy Seabee general surgeon during the unpleasantness in Viet Nam, and spent the remainder of my ten-year service as a neurosurgeon in a major naval regional medical center. I’ve lived in every section of the country, saw all the inhumanity of man to man, practiced in private settings large and small, the military, academia, and as a medical humanitarian in the Third World.