It’s actually a whole book series by Erin Hunter, (Warriors) & it also has manga and graphic novel versions if you’re more into comics and illustrated stuff.
So you can read it as regular novels or dive into the drawn versions too!
More about it here: Home | Warrior Cats | Warrior Cats
(PS: The game is just based on the books. The characters aren’t official; they’re someone’s original characters inspired by the series.)