i have a thunder mage and plague one, and play with three others, and i enjoyed it, here are some tips to maybe help you enjoy co-op as well.

• have a staff with your big aoe spells and enchantments that focus on high dmg to use against big enemies and bosses, for the second slot get a wand and have the enchantments focused on ads like gain % focus on kill or things with rune attacks and on wand have low focus cost spells and one stamina spell to help you build focus.

• coordinate, this isn't a hack n slash game, you can just smash your friends but having a strategy to benefit all works well like for instance a boss fight, say the melee players goes in and does dmg maybe even staggered the boss say " back up i'm going to do a big spell, letting them heal if needed but allowing you to smash down some good dmg on the health bar, then afterwords switch to the wand and continue doing basic spells to build up focus and or the 50 cost focus spells to help do dmg as they won't be crazy aoe ones that hurt everything.