36 magma totems/36 nova totems/36 fire elementals and 36 thunderstorms > mage priest aoe with that many characters

Grounding and tremor for every group

Just imagine the insanity of target random on 36 characters + chain lightning, not like you would really need to very often when your totems and thunderstorm will just auto kill everything though

Hope the guy makes some city raid videos, because i'm sure they will be incredible to watch