J.R.R. Tolkien was the one who originally created orcs, yes. Although they also appeared in some of his other Middle Earth-related books, mainly The Hobbit, which is the prequel to The Lord of the...
It depends on who you are. the more power you have on your own, the more power it will give to you. Sauron uses it to control middle earth, and anyone else powerful enough, like Gandalf, would be...