i am making a rat race mod but i want to make it atleast a little lore friendly. are there any mentions of some humanoid creature that could possibly be a rat?

Not really, not even wererats I think. You'll have to create them from scratch.

I think you're looking for http://img405.imageshack.us/img405/8915/untitledxa5.png

You could always make your own....

I'm pretty sure there is no mention of any form of rodent-like race in the lore of the Elder Scrolls. In other words, you'll have to make up your own, not that there's anything wrong with that, lots of mods don't fit the lore perfectly and are still very popular, it just won't be completely lore friendly.

Took about 10 minutes to find and it's all I know of.
http://www.imperial-library.info/pge3/other_lands.shtml

"Contemporary scholars find references to pirates with rat-like features, and still others who appeared canine, suggesting Akaviri cultures yet undiscovered and perhaps extinct."

>rat-like features

It's under the Akavir section. Second paragraph.

You'll have to make it up from there, I suppose.

EDIT: Sentence structure, spelling mistakes, etc. Also, there is mention of the same thing in Guide to Akavir.

This is a fantasy universe where Goblins, Ogres, Trolls and Minotaurs exist.

I'm sure that Kobolds or similar creatures could hypothetically be worked into the existing framework as a viable race. I don't recall they were ever mentioned before but a lot of things weren't until a certain point.

Yes they are called Skaven

Don't try to make friends with them, trust me.