Simple way to get the Gortesh No traps Achievement.
Getting to Gortesh
The easiest way is to use Enhance Leap on each member of your party and jump from to roof tops on to the South West side of Wyrm’s Rock Tower.
Once there there will be some scaffolding that will allow you to climb up higher. Watch out for traps on the ground, lead with your most perceptive party member.
You will gain access to a bell tower, there will be a leaver that lowers a ladder to the level Gortesh is on.
Getting in Position and Fighting
Here is my screen shot of where my party stood.
The easiest way to replicate this is to hold shift and get your front liners up to the edge of the vision cones(in red) but not in them. once you are comfortable with that placement. Bring up your support and caster characters.
So we cant move, if we go backwards traps will activate, if we go forward traps will activate.
We use ranged attacks. In my case, I used bows and cross bows and the occasional fire bolt. And throwing. Gortesh might get knocked back out of range, so throwing a bomb behind him, firebolting it will push him towards you.
Dont worry about the two things on the wall buffing him, they dont count. Just sit here and hit him with as much ranged fire power as you can. If the guards approach, hold the line and cut them down.
Took about 4 rounds to down Gortesh and get the achievement and I’m not very good at this game nor specing my characters/
Best of luck!