Communions

How communion masters and slaves work: the path levels slaves add, how spell fatigue is divided, who counts as a participant, backlash, and setup.

verified 6.37updated 2026-10-02 · Jake9 min read

A communion is a pairing of two kinds of mage in one battle. The masters cast the spells that matter. The slaves give up their own turns to make those masters stronger and to soak up part of the fatigue the casting causes. This page explains the arrangement as the manual lays it out: what a valid communion needs, what the masters gain, how the fatigue is shared, and what happens when the masters are lost.

Everything here is the manual’s wording turned into plain rules. We have not re-measured any of it, so where the manual is silent the last section says so rather than guessing.

What makes a communion

A communion needs two parts, and it does not exist unless both are present.

• A communion master, who casts the master spell.
• A communion slave, who casts the slave spell.

The two casters each cast one spell, so a communion costs at least two mages their turn. The manual’s phrase is that a valid communion cannot exist without both spells in effect.

Three kinds exist, each with its own spell pair and its own set of members.

• Communion (Astral): Communion Master and Communion Slave.
• Sabbath (Blood): Sabbath Master and Sabbath Slave.
• Chorus (no path named): Chorus Master and Chorus Slave.

The Sabbath spells cost blood slaves to cast, which the Astral pair does not. Chorus is the singers’ version: the manual says Spellsingers of Man can cast it, and only Spellsingers. The manual calls the Sabbath and the Communion almost identical, and it uses the word communion for all three when it describes shared rules, as this page does.

One of each kind can be active at once. Each has its own masters, slaves and bonuses, and they do not mix: a Blood mage who is a Sabbath master gets nothing from Astral mages who cast the Communion Slave spell.

What the masters gain

A master gains extra levels in every magic path in which it already has at least 1 level. A path the master does not know stays unknown. Every master in the communion gets the bonus separately.

The size of the bonus depends on how many slaves there are. The manual gives the rule as a power of two: a master gains n extra levels in each known path for every 2^n slaves. Its two examples are 2 slaves for +1 and 4 slaves for +2. Following the same rule, 8 slaves would give +3 and 16 would give +4, though the manual does not list those. The bonus is a step, not a slope: three slaves earn the same bonus as two, and the manual says the bonus drops as soon as the slave count falls below the number that earned it.

• 2 slaves: +1 level per path (the manual’s example).
• 4 slaves: +2 (the manual’s example).
• 8 slaves: +3 (follows from the rule).

The bonus counts when the spell cost is worked out. The manual states that levels gained from the communion, and from every other source, are included in the fatigue calculation. A master who becomes stronger through the communion therefore also pays less for each spell, through the normal rule for extra levels described on the fatigue page.

How the fatigue is shared

The aim of the arrangement is to move fatigue off the caster. For each spell the master casts, the game does three things.

1. Work out the spell’s fatigue cost, using the master’s levels with the communion bonus included.
2. Divide that cost by the number of participants, which is defined below.
3. Adjust each slave’s portion according to how its skill compares with the master’s.

The adjustment is a ladder of four steps, comparing the slave’s level with the master’s level:

• Slave level equal to the master’s: portion unchanged.
• Higher than the master’s: portion halved.
• Lower, but not below half the master’s: portion doubled.
• Below half the master’s: portion multiplied by four.

The ladder reads best from the top down: the closer a slave matches the master, the cheaper it is to include. A slave whose level is higher than the master’s carries the lightest load.

Worked example. A master casts a spell whose fatigue cost comes out at 12 once the communion bonus is counted. The communion has two slaves, so there are three participants and each portion starts at 4. If the master’s level in the relevant path is 5, a slave at level 5 takes 4, a slave at level 6 takes 2, a slave at level 4 takes 8, and a slave at level 2 (below half of 5) takes 16. The numbers are chosen to show the ladder; they are not taken from any particular spell.

The manual does not say what the master’s own portion is, or whether the ladder applies to it. We therefore give no figure for it.

The Communion, Sabbath and Chorus variations

The manual lists some small differences between the kinds. For the Communion it says spells take 25 percent longer to cast. For the Sabbath it says the caster takes only half as much fatigue, while the slaves take 20 percent extra. For the Chorus it again lists the 25 percent longer casting time, and adds that a slave who loses consciousness drops out of the communion, so it takes no damage when the masters cast more spells.

The manual does not say whether the longer casting time applies to the whole cast or only to part of it, and does not say how the Sabbath’s extra 20 percent combines with the ladder above. We state the figures as the manual gives them and no further.

Who counts as a participant

For any one spell, the participants are the master casting that spell plus every friendly communion slave on the battlefield. The count is made for each spell separately, which is why the divisor can change during a battle as slaves join or leave.

The manual says that slaves cannot take any action of their own while they are part of the communion. They do get the benefit of any self-buff the masters cast, meaning a spell that targets one unit at range 0.

The communion ends the moment it has no masters or no slaves. The masters’ level bonus falls away step by step as the slave count passes below each threshold, before the communion ends outright.

Backlash

If every master is dead or has fled the battlefield, the communion breaks, and the slaves suffer a backlash. All slaves are stunned for roughly one round, and each takes fatigue damage of 3d50. That is a severe blow: three rolls of 1 to 50 summed, so the average is about 76, and a slave already tired can be pushed past the point at which a unit collapses (see fatigue).

The manual states the rule once and gives no more detail: it does not say whether armour or protection changes the damage, and it does not say whether a Sabbath or Chorus break behaves the same way as a Communion break.

Joining without casting

Four magic items let the bearer take part in a communion with no spell cast: the Slave Matrix, Slave’s Heart, Master’s Athame and the Crystal Matrix (which has no page here yet). The bearer still has to be a mage, meaning someone with a level of 1 or more in any path except Holy. Astral or Blood levels are not required. This is the easiest way to use a communion with a mage whose own paths do not match.

Grand Communions

The word also names a different rule. A mage with the Grand Communion ability can cast a global ritual, and other mages with the same ability can join by using the Grand Communion order. Each joiner adds its skill in the ritual’s path to the strength of the casting or of a dispel attempt. The manual works one case: a dispel with 12 extra gems, helped by two mages at skill 2 and four at skill 1, adds 8 from the helpers to reach 20. Dispel is an astral ritual, so the helpers’ astral levels are the ones counted. A Grand Communion has no slaves and no fatigue sharing; it is a way of adding strength to one ritual.

Setting one up in practice

These steps follow from the rules above; none is an extra rule.

1. Pick the kind first. Astral mages use the Communion pair, Blood mages the Sabbath pair, and Spellsingers the Chorus pair. Mixed kinds do not combine.
2. Have at least one master and enough slaves for the bonus you want. Two slaves give each master one extra level, four give two, and the bonus is lost if casualties push the slave count under the threshold.
3. Script the master spell and the slave spell in the same battle, one on each mage, so that both are in effect. The manual does not say in what order the two must be cast, so do not rely on either order.
4. Treat slaves as out of action once they are in. They cannot act on their own, so do not give them other orders and do not count them in your plan for the turn.
5. Pick slaves whose level is close to the master’s. A slave at the master’s level or higher carries a cheaper share than one far below it.
6. Protect the masters. If every master dies or retreats, each slave takes the backlash, so a communion with an exposed master is a risk for every slave in it.
7. Cast self-buffs from the master, not from the slaves. Slaves share in a master’s range-0 self-buffs.
8. For the items above, no cast is needed: the bearers join automatically. They must still be mages.

What the manual does not say

• The master’s own share of the divided cost, and whether the slave ladder applies to the master.
• How a slave that is unconscious or has fled is counted, beyond the Chorus rule above.
• The order in which the master and slave spells must be cast.
• The bonus levels beyond four slaves, which follow from the rule but are not tabulated.
• How the longer casting time and the Sabbath’s 20 percent extra fatigue combine with the other rules.
• Whether armour or protection reduces the 3d50 backlash.
• Whether the backlash applies to Sabbath and Chorus slaves in the same way.

For how paths and levels work in general, see Magic paths. For the spells that communions are used to cast, see Combat magic.