Vervolses Explained:
More commonly known by the later Norman spelling "Werewolf" they are much more simple in the original mythology. One major difference is that they are not undead and will die the same way any wolf would die when in their wolf form and any way a human would die in their human form. Vervolses don't feed on human flesh, holy stuff and silver has zero effect on them and you can't become a Vervols by being attacked by one. Another key difference is that a Vervols chooses when to become a wolf or a human and nothing forces them to change. The idea behind the creature is that a human and a wolf spirit have become fused in one body, either a human or a wolf. There are multiple ways this can happen but the most common is that if a human boy and a dog are the same age within a month of each other and they are close friends then if one dies their spirit can enter the other's body. Sadly I did find that in the story the creature is either entirely wolf or entirely human and no furry crossbreed or mid change version exists. Also Vervolses give birth to either human or wolf children and not other Vervolses depending on who they laid with to create the pregnancy so hairy humans are not Vervolses. Stories often say about Vervols that every month they become a wolf and sneak away to visit their wolf pack on the full moon but then return by the morning to rejoin their human family in human form. Common to the stories are Vervolses that are mistreated by their fellow humans and run away to be a wolf instead. Common to these stories are two factors, 1, the parents of the Vervols try to keep the person captive to prevent it, often tying a tightly bound wreath of Wolfsbane around their neck so as to create a pungent smell that only canines can smell making them not want to be a Vervols, or locking them in a room to which they turn into a wolf and dig through the dirt floor of the house to escape, and 2, once the person has become a wolf they later attack the family's cattle or sheep with the wolf pack and the family kills them by mistake, only realizing what they have done afterwards. A staggering amount of much later accounts tell of parents that want to exorcise the evil spirit and call a priest. When the priest tries to remove the spirit, since the two spirits are one they remove the child's spirit along with the wolf's killing the child in the process. The parents then realize their folly as the child spirit runs off into the woods never to be seen again. In some stories if the parents are good parents allow the child to become a wolf and disappear during the night every month knowing that they will return by daylight. In these stories they go wandering off into the forest to find their child when they don't come back one time and become lost later encountering a bear which would normally be certain death. Their child then in wolf form immerges and fights the bear scaring it away before revealing to the family who they are and telling them that they have chosen to be a wolf and guide the family back home before returning to the forest with a tearful goodbye. It's likely that in these stories the forest represents the afterlife and the child turning into a wolf is a representation of a disease that which causes children to become feral in short bursts every so often before they eventually die or rabies. Following the child's death, the parents have a near death experience from the shock or a lucid dream where the ghost of their dead child says they can't go with them and guides them back to the land of the living.
Vervolses are one of a few mythological creatures that have had their rules about how they function massively altered by much later Christian influences. The Christians were keen to stamp out the old beliefs in fairies so they often depicted them as malicious creatures that killed and ate humans. Key to the Christian versions of the stories is the creatures being notoriously difficult to kill and only holy objects, priests or expensive items that could be acquired only from priests such as salt and silver were able to kill them. Similar to vampires, ghosts and ghouls (zombies), Vervolses were afflicted and had no control over their actions because they were being manipulated by evil. This is important as if they just went around saying that everyone's relatives were evil they would most likely be hated but saying that the afflicted relative had no choice in the matter meant that you weren't attacking the family's relatives directly.
Though many think the stories were created to explain hairy people or tribes that wore wolfskin to keep warm, they were most likely created to explain why children went missing, which was really down to neglectful parents not watching their children properly so the kids wandered off into the forest and either got lost and starved, injured themselves and died of septicemia or were attacked by wild animals such as bears. This explanation makes sense as almost invariably the children that become Vervolses belong to terrible parents.