I think it was one of the most fun fights I have had. Did it on PotD/Trial of Iron with 5 fighters, all with Int 3 (so basically no will defense) and there was a lot of micro managing (like running away everytime the dragon casts Cloak of Death). Probably took me about an hour to complete it, but I missed all of that "standing on symbols"-thing so probably could have done it faster if I had understood that

Killed it on lvl 13 POTD upscalling only UP, with no optimized/leveled equipement i picked along the way. Strategy was simple, best defence is offence.

 

Eder and Aloth - dualwield sabre warriors, Ydwin - dual pistol and main dual pistol ranger/thief, all multiclassed, Xoti was  a pure priest tank.

 

Sleep with food that gives 2 penetration, equip everyone with penetration potions, atack speed potions and damage potions. Took me like 5 tries, untill i went no brainer autoatack/skill spam fest. Killed him in 20 sec, just where potions went off.