I also play on hard,defeated it at level 12.I didn't find it very difficult,only Eder dropped 1/4 health once,others were intact.but I pre-buffed,don't know if it counts as cheese, rest in the inn,eat some food that kind of stuff,Eder engages the dragon at the lower right corner,burns a scroll of +20 defense protection and uses his own +20 defense ability while the others station at the upper right corner, drink some speed potions, burn a scoll of accuracy and a scroll of defense,cast prayer against fear,send some figurine summon and cast confuse on the minions,then focus on debuffing the dragon,will attacks are more effective,miasma of dull-mindedness,borrowed instinct,and then veombloom and call to slumber,he's down for 20 sec,that's pretty much the end of it.if the druid's storm spells don't have bug,I think it'll be even easier,magic users are just that good.I used the same strategy on the adra dragon too.