Ok so you’ve beaten the baddies. You’ll have to put out the fire that’s blocking your way to continue on your way. You’ll get to a town grinder and you’ll see a funny reference to Braveheart. In the corner near the grinder you’ll see the Blade of Chill sword in the corner. Just put out the fire that’s blocking it and you can grab the sword.
You’ll have to enter a burning house and in that house is the Conflagration Magicka spellbook.I personally don’t use it very much. It’s a complex spell and I just don’t think it’s worth the hassle. It might be good against the swarm of bomber goblins you’ll face shortly after however.
You’ll get to a Castle and unfortunately the King is barricaded in his castle. The guards plan to blow up the door however the fuse takes 3 minutes. There will be endless waves of monsters attacking you. You can constantly heal the guards who will kill everyone, or you can kill everyone yourself. The third option which is the quickest is simply to cast a fire spell on the fuse which blows the charge. It saves a lot of time especially if you’re going for the Mission Impossible achievement (Beat the game under 4 hours).
After you destroy The Machine the boss warlock will attack you himself. He attacks the same as the regular warlocks except he has extra hp. After you defeat him he’ll try to attack you with a lightning spell except the King will throw him in the pit like in the Star Wars movie.
That completes Chapter 4.