Ok, as a disclaimer: I know and understand why there’s no cats and no rats.
However, my players like this idea so I’m going to try it regardless. I’d like to propose it (although I fear a backlash). My only hesitation with implementing this is a real possibility of polluting my Territories. Here goes.

The Rats of NIMH have left for Thorn Valley and have ended up in the territories traveling from the south. They came in the winter and set up shop in a thick bramble. Although they have decided to drop the theft of electricity and go into the country they have brought with them a few advanced mechanical items. Not being able to find Thorn Valley they see no reason why they can’t share the territories as equals with the mice.
Plot is something like this: Over the course of the year, starting in spring, the guard naturally investigate these large unusual creatures and find them peaceful enough. (here is where I expect players to take the reign, hopefully without knowing) either the players are suspicious or there is a rat that thinks himself superior and seeds doubt and whispers warmongering. Will the players find a peaceful solution? Perhaps this will lead to war? In either case will the rats decide to stay or perhaps move on and find the true Thorn Valley. (yes they will move on… or die in a war, whichever my players choose)

Now if I can just figure out how to keep the “tech” from leaking into the mouse world. I like my low-fantasy thank-you-very-much. Humans of course are easily kept secret as the rats are quite fond of living in this new world of mice without the muddying of humans, and have no intention of mentioning them even under duress. I’ve come up with a few solutions for this pollution in most events (war has an explosion destroying the tech, peace has them taking everything with them, etc.) but I don’t know what to do if the mice want to set up trade. (I’m thinking the rats will be firm on that… of course that might be the trigger for conflict!)

Or could just leave the tech in, creating a whole new dynamic to the system.

Don’t hate me now. Hope this inspires you!

note: for anyone who hasn’t read Mrs. Brisby and the Rats of NIMH or seen the Don Bluth film “Secret of NIMH” I suggest to go out and find it immediately. Very inspiring for MG.

You could simply replace Weasels with Rats, and keep all their current stats and such from the book. Their Nature descriptors would be quite similar so as not to force a change.

As for a cat, that could be done quite easily by using one of the animals in the book as a template.

yah but I don’t like cats in MG. probably because they’re domesticated.

That’s why I included the mention of cats.

I like the Nimh Idea. I would like to see any ideas you have on the effect of the rats. As for the tech effects distace is a limiting factor on how much tech, just look at the effect of the colonal powers into the harsh conditions and lack of parts. The rats did make use of pulles and levers.

On a darker note rats are lager then mice and would be prone to domidate the smaller mice, populations rates are about the same so the mice can not over run rats with numbers. So what you do with that 2 cent of advice is up to you.

As for cats…easy woves lot more filling then a few mice.
wild cats should be in there more 2 cents