[Karlem]

Reverse comunion uses the fact that caster cast following their placement in the army setup page. So if you cast comunion slave but casta every turn before the master you will be able to cast.

The idea is using boosters, phoenix power, summon earthpower, light of northern star, astral power... so that slaves (the majority) can now cast better spells instead of S1 crap. Of course, you have to be carefull so that mages do not die of fatigue and it's quite risky if you set it up incorrectly.