Also, while I haven't PvPed yet, if you see a wizard wind up his staff and slam it on the ground, that's the sign he's casting spell disaster. It is accompanied by a large purple AoE on the ground around him too, this AoE also exists when he's a co-star and has no staff to slam so watch for it! Once the orbs are released, you can avoid them as even when they have the homing bonus for co-star they are pretty slow, but if you get out of that AoE before the orbs are released, it gives you an even better change of evading damage.