I did it solo also pretty easily, took extra time to clear the two main areas, void rockets worked well on all the psion and wizards, but sniper for everything. The beserk modifier made it so that dark blade wouldn't teleport away very much so I just kept change sides of room and putting full clips of sniper into his head. Clear adds when they spawn and you'll have a 1 on 1 with boss which makes it easy. A trick to quickly clear cursed thralls is to run towards them and jump over them, they self explode