[Maerlande]

Your second statement is correct militarist. They can only cast spells of the paths they had before. But they do get boosted for fatigue.

Here's a typical reverse:

Yogi S1: Communion Slave, body ethereal, Soul Slay, SS, SS, Cast
Yogi: same
Yogi: same
Yogi: same
Yogi: Same
Yogi: same
Yogi: same
Yogi: same
Yogi (M): Communion master, PotS, personal luck, resist magic, SS, cast
Yogi (M): Communion master, LotNS, astral shield, SS,SS, cast

8 slaves: Each master is now +3 S. PotS gives all slaves +1. LotNS gives all slaves +1. Remember to give each master one pearl.

This communion can cast all day.

For real fun add slaves and a master with another path. Say ES. Then you add invulnerability. Or nature and add resist poison, elemental fortitude, and so on.

And for even more fun use one blood master.

B1 master: Sabbath master, buff, buff, buff, reinvigorate
This sets all slaves to zero fatigue.

You can also give the masters bows:
Master, PotS, buff, buff, buff, fire
This allows about 1 master for 3 slaves or so.