This is really good, but I do have a few bits of feedback.
1. Check your capital letters are in the right place, and you need to make sure your puntulization is accurate as well. For example, one of the sentances that stood out to me most for needing more capitalization is this one:
“It’s Greystripe he's dead!” The one behind him was dangling a limp body from his jaws. "We'll deal with it later for now!"
"Who are you?" The spotted one one said, thrusting herself through the commotion.
The letters and puntuation in bold and italics are the ones I have added in/fixed. Please double check your writing!
2. I know I didn't use them, but I reckon that this piece of writing would be much more fluent if you added paragaphs.
3. You have written a character's name two different ways;
Graystripe
Greystripe
I reckon you should choose one spelling of it, as neither are incorrect, but it would be easu\ier to follow if they were the same.
That's all of my feedback. This is a really cool piece of writing, but it can be improved. Continue working on it, and maybe you could make it into a book!
Keep Writing!
-Pik4corn