[thejeff]

I ran some tests with this (and a few other communion things)

Spells cast by slaves do not affect the whole communion, so having a communicant carry the Shield does not work.

Assuming the use of Crystal Matrix and Slave Matrices.
The Crystal Shield does boost the path of Slaves, at least those who act before the master.
I'm not sure what Ich saw, but I definitely saw the boost. Maybe his master acted before the slaves?

And in reference to a suggestion in another communion thread, slaves paths may be boosted for fatigue purposes, but not for spells they cast themselves.

So does any of this qualify as a bug? I like slaves being able to act if no Masters are casting, but being able to cast if they act first seems abusive. It certainly isn't the intended behavior.