Dominions 3: The Awakening/Magic/Communions

Tips

 * Regen for slaves (use Shroud of the Battle Saint with a N-bless or Rings of Regeneration) can sometimes be much better than reinvigoration 5 for slaves.
 * Alternatively get a master to cast Soul Vortex, so the slaves all Soul Vortex each other + their chaff guards. Soul Vortex only saps 1HP from each neighboring unit. Spaced apart, each slave could have 5 regenerating guards (trolls, werewolves, blessed Flagellants, etc) to act as the hp source. Just E4/N4 bless would give you +12 reinvig per turn with 5 guards, and if you can pop on Summon Earthpower you're at +16 reinvig for happy casting.
 * Priests with only H-path magic get boosted by a Crystal Matrix per normal, but a Crystal Shield has no effect. To benefit from Crystal Shield, the master needs at least one level in non-H magic. However, a Crystal Shield bestows 8 base fatigue even to 0-fatigue holy spells, so using one for holy communions might not be the best idea anyways. A bug allows an H-only priest with a Crystal Matrix to multi-cast spells in the same round = number of H-only slaves.

Types of Communions

 * Standard Communion: This is the classic setup where the Masters all come first in the listing order, followed by the communion Slaves. Hence the masters cast, and the slaves are there to soak-up the resulting fatigue. This is the classic way to get multiple casters with 5 or more picks in their respective magic paths for casting the most powerful battlefield spells.
 * Booster Communion: This starts out like a Classic Communion, but with only 1 Master who is armed with a crossbow or wand and each slave scripted to cast Communion Slave then Cast Spells. The Master casts path-boosting spells that will benefit the rest of the communion like Power of the Spheres, Light of the Northern Star, Summon Earth Power, Strength of Gaia, etc but then is scripted to fire closest. Each round in the ensuing battle that the Master fires his crossbow rather than cast a spell (he has 12 ammo, so it should last 24 rounds), the Slaves get to cast spells, but now they cast with the increased benefits from boosted paths! The Booster Communion is very safe for the Slaves: since the Masters stop casting for 24 rounds it is very unlikely any slave will die from over-fatigue. Both the Ethereal Crossbow and the Piercer can be used underwater.
 * Reversed Communion: A reverse of the classic setup, where all the Slaves come first in the order list, followed by the Masters. Scripting is like a Booster Communion. This setup allows both Slaves and Masters to cast each turn, with the slaves benefiting from boosted paths, but is more risky since the slaves will be accruing fatigue twice as fast till they pass out. As long as the battle is over within 12 rounds or so, there are generally no Slave deaths from over-fatigue.
 * Delayed Communion: This can be any of the previously listed communion types, with the difference that the participants first cast up to 4 non-personal-buff spells before they join the communion. An example would be scripting each mage to cast Body Ethereal 3 times, then either Communion Master or Slave. In battle, your entire team of magi will cast Body Ethereal on any nearby squares containing friendly units who are set to Hold and Attack before joining in a communion.
 * Buff Communion: This is a special variation on a Booster Communion, generally requiring more Masters, since each master casts self-buff "personal" spells such as Astral Shield, Personal Regeneration, Invulnerability, etc whose effects are also transferred to the Slaves. You want to load up the Slaves with as many beneficial buffs as you can, hence more masters are needed. Once the masters stop casting, the slaves are free to move up closer to the front line and act as blockers/ or for close-range combat spells.