This fight is pretty hard, true. I got there a little bit early with I believe level 3, and it took me all my consumeables and every spell I had to win this fight.
I mean, it's fair that it's this hard, since this is where you can start travelling around the world, and I assume an alternative end to act 1. Could use some heads-up though, if you are not prepared and haven't saved in a while, you probably won't beat it and lose your progress.
