The voiddragon fight wasnt that hard. The key to success is cc as all the others have pointed out. Once I knocked the dragon down, my knight took out almost all of the dragons hp with flurry, oath of des buff and the trait that increases dmg against crippled/slowed/knocked down enemies.
The only problem was that Astarte never moved during the fight and only casted water of life. I dont know if that is a bug or not but she was useless in the fight and didnt even heal herself. In the previous fight against the deceiver she would move,attack and cast a different spells.
