I tried several build items on Eder as a tank, but no luck. Dorudugan still crits me with 150 deflection. True, my armor is a bit low - 12 crush-14 pierce-16 fire.
I have the bad feeling this fight is impossible without some form of chanter - as a tank with regeneration or simply for the summons as meat shield.
If someone have a luck with fighter tank, Eder for example, let me know.
Also, as I said in my first post - i am playing on Veteran.