This fight held me up for a good hour trying to figure out a tactic here.. I only survived with pure dumb luck to be honest.
So you need (imo)
Medium! Potions and healing scrolls for healing on warriors
Rain (cast before the combat begins)
Regeneration
Strong Regeneration
Knock Down Martial skill on both your fighters
Fire Elemental (no way around that, if you don't have it on your mage, scrolls, but I honestly wouldn'd know how to deal with 3 bosses without at least a fire-elemental being able to tank 1 of em)
Ice Elemental (yes, you read right) ;P
As for stuff to kill, the thing you want to kill first is the poison guy to the right, have your warriors (attempt) knock-downs on the skeleton dude and try to somehow stun braccus (though I still can't remember whether it was knock-down or stun or freeze..., SOMETHING stopped Braccus for a while and saved my behind) so you may have to test out to what he's weak. Once poison guy is down, you will notice things become much easier... since without poison clouds, the entire battlefield won't be on fire 99% of the time.
If you die on first attack then move your guys apart (unlink) and hope for the best, (sorry, no idea how else to do that ,p) it was pure luck that I only took 50% damage on that, I cast healing spells with mages and just slugged through
*Remember, time passes during dialog, so your protection and especially rain count down if you are slow*
And here I go and forget the twin fire elemental, try freeze or stun on him.
Basically, for me this battle only was a victory once i used EXCESSIVE attemps at stunning or interrupting these guys. KNock down, ice, electricity, and ice elemental to maintain control, I used ice elemental even more than the fire elemental (obviously that fire elemental is useless against braccus and twin) and again, you need to have some luck...
I haven't yet found a tactic here that would really make me confident though. When 4 bosses come at you things can go wrong very fast.... so yeah
