[Mightypeon]

Nope, there is one communion, and you can very much start with casting the slave spells.
If you want a communion that only buffs the master, you usually put the master first,if you want a communion that buffs the slaves, put the master last.
If you have the master as last, the slaves will not be boosted in the second turn, but imho the trade off is much worth it.
I think you have been confusing 2 types of common comminions.
There is the normal communion in which the slaves simply act as fatigue absorbers for the masters. Like, Pyhtium likes to do. There is also the reverse communion where the master simply casts buffs, and the slaves thus cast improved spells. In you case, mystics are way to cool to be used as communion slaves for another mystics, so reverse communion is a nice idea.


Something else one can do with Blood nations is having a mixed communion of Astral on Blood. Reinvigoration from the Blood school can in some cases reset fatigue on the entire communion to near 0.