That Erin Hunter can be harsh?
No but they can make the cats in Warriors harsh.
Mark Twain is more famous than Erin Hunter. He wrote a lot of classic books that most people have heard of and/or read. Erin Hunter is a modern writer, and very popular, but I have never seen a biography of her in a bookstore. Erin Hunter probably has a larger following, though (check out the Warriors message boards).