[Mightypeon]

A mage with a fairly early turn order casted communion master in turn 4 I believe, if I remember correctly before many of the communion slaves, who then ceased to cast themselfs. This noticably reduced the number of rocks falling down.
He then proceeded to cast other random staff that prevented the comminion slaves from blowing up things as intended.
I am not entirely sure wether this would have made a difference though. I am also quite certain that the Firebird and its solar brilliance hurt Maverni more than Agartha, especially since Agartha put up AntiMagic, and thus had superior MR.
Imho, the AI should never cast communions by itself.