Wererats are therianthropes who transform into rats or half-rats. As other such creatures, they are hardly hurt by steel but very vulnerable to silver.
There are two most common ways to aquire arouranthropy: the first one through a curse[1] and the second is to simply have a wererat parent.[2][3] Being bitten by another wererat, while popular in folk tales, gives only a very small chance of becoming one in reality.[1] Those who are born as wererats are able to fully control their shapeshifting abilities,[2][3] while those cursed or bitten change into their wererat form only during the full moon.[1] Those who became wererats during their lives however are the only ones who can be cured.[3]
Therianthropy diseases, including arouranthropy, appeared in the world after the Conjunction of the Spheres, affecting nonhuman and early human populations alike.[1] Rats and wererats of Vizima sewers served as experiment material for geneticist Idarran of Ulivo in his youth: one of the results was a bulky, giant wererat able to survive a burst of arrows.[4] Centuries later, an old hierophant from Rivia formed a theory that each monster, including a wererat, has its own ecological niche and a place in the food chain; he died eaten by a colony of wererats two days after explaining his theory to witcher Geralt.[5]
Wererats are the only therianthropes who create strictly hierarchical societies. They live in colonies consisting of two to four arouranthropes and a number of rats and mice; they do not accept pseudorats and hate them as those are not true rats. Arouranthropes have an aversion towards lycanthropes and fiercely hate ailuranthropes.[1]
The Witcher[]
They were supposed to appear in game as monster lurking in sewers of Temerian capital Vizima but were later replaced by drowners.
The Witcher: Monster Slayer[]
Wererats make an official game debute as enemies. They can be found near human settlements and are mostly nocturnal. There are 4 variations of wererat: wild wererat, wererat warrior, wererat gatherer and Thundster. The latter one is more of an easter egg, bearing resemblance to Pikachu in the Pokemon franchise.