It's not just that he is terrifyingly powerful, although he certainly is. It's that he is terrifyingly powerful and Endarkened, and all of the other Endarkened want to conquer the world and kill or enslave all who oppose them and bring their dark god back into the world to rule it forever. This is naturally a troubling prospect.

Someone is coming this way? Two visits in as many hours, after ten thousand years of solitude. How curious.