Rats in Mouse Guard
From Burning Wiki
Rats are found (rarely, but present) within the boundaries of the Territories in the Deeps of Darkheather campaign setting. As with Mice and Weasels, Rats possess language, culture, and technology (which they, admittedly, mostly borrow from Mice and Weasels). They are effectively mysterious and neutral figures in the Territories: their kind are not well known at all to the Mice (slightly more well known to the Weasels). The consort with both other races, but only on rare occasions. Their (re-)appearance in the Territories has only been within the last three years, since the great war.
Rats are similar in form to Mice: they could indeed be cousins. They are longer, and generally lankier than Mice; however, because of their natures, grossly fat Rats have been known to exist. Their size ranges from "small adult Rat is about the size of a large adult Mouse" to "large adult Rat is about twice the size of a large adult Mouse". Their snouts are generally pointier than Mice, and their ears (proportionally) somewhat smaller. Their colouring is roughly the same as Mice, although tending more towards browns and blacks than the wider range of fur-colour found in Mice. White-furred Rats, with red eyes, have been spotted (very rarely indeed) in the wild.
Very little is known about Rat social organization in the Territories; nearly all encounters with Rats have been with solitary individuals (or, very rarely, small groups of two or three). Rats seem nomadic by nature: they don't seem to build homes, so much as borrow them (when they bother to live in a fixed, sheltered, location at all). Rumours do exist of a tradition amongst Rats to indenture Mice and use them to pull little covered wagons in which a Rat might live; but no-one has ever seen this, and all Mice generally acknowledge it is a folk-tale related to warn younglings.
Rat Nature is different to both Mouse Nature and Weasel Nature. Rat Nature does encourage them to flee (although not hide) like Mice, and it also characterizes them as wily and clever like Weasels. Rat Nature drives them to sneak about, enjoy the pleasures of other people's things, and generally be an irritant to other, more settled cultures. Their Nature descriptors are: Roaming, Sneaking, Knowing, Acquiring.
Here is a collection of Rats you can use as Denizens.
Nature (Rat): 4 Resources: 2 Will: 5 Circles: 4 Health: 3
Skills: Deceiver 4, Haggler 5, Pathfinder 4, Persuader 5, Mouse-wise 4, Weasel-Wise 4
Traits: Alert (2), Sharp-Eyed (2)
Gear: Staff, knife, satchel full o' baubles of dubious value