Generally I had someone posted up right near that had high dex (good spot for a ranged character anyway) that way they can destroy it before any goblins get to it. Also had someone up top to take care of the 2 human assassin guys. I view that fight as essentially 3 smaller ones, the 2 guys up top, the goblins, and then ragzlin. If you can take out most of the first two the rest of the fight is much easier.

The other option (albeit less ideal one) is to knock him into the pit to the right of him. Although I don’t think you can get his parasite or loot if you do that.

Also I should point out you should be at least around level 4 when you fight him, otherwise it will be significantly harder