[Endoperez]

Ouch, nasty trick.

Reverse communion is pretty easy to use. The only thing you have to remember is to keep the master from casting spells before slaves. The master can be last in order, or can retreat, or you can give him a bow and script him for Fire after he's buffed the slaves.
I used it to make a host of my C'tis Shamans receive Power of the Spheres, and I also cast Light of the Northern Star. The Soul Slays didn't do as much as I had hoped, but they were just my researchers.