This combo works very well for me
Character 1- Nephil, Swordsman/Archer
Character 2- Slith, Spearman/Archer
Character 3- Human, Mage/Priest/Archer
Give each character the takes extra poison damage trait, Elite Warrior for #1, Natural Mage for #3, and probably Elite Warrior for #2 (been a while since I have played )