Whether born naturally or afflicted with the curse of lycanthropy, wererats are lycanthropes who can switch between human and rat form and are common in crowded and dirty cities. They are one of the two most common forms of lycanthrope (the other is werewolf) and one of the most feared. They are also among the physically weakest, so rely on stealth and cunning to survive.
Like all lycanthropes, wererats have multiple forms, the most mundane forms they take are either as regular humans or rats. Whilst an infected wererat human form looks like they did before they were cursed (although sometimes taking on rat-like mannerisms) natural wererats tend to be short and wiry, often with a nervous disposition and darting rodent-like eyes. Wererats can also take on a hybrid form which combines their humanoid form with rat features. In this form they gain a long, twitchy tail, fur covers their whole body and their head becomes that of a rat giving them a nasty bite.
Wererats almost always dwell in cities for it is there where rats and humans most commonly co-habit and so it is where a wererat can most easily blend in. Many cities have wererat infestations from lawless slums like Riddleport to well-run cities like Korvosa. Because of their ability to blend in as rats and the mobility this grants them, wererats often find work in a thieves' guild.
