Wizard's Communion

Wizard's Communion is a canonical MuVi Gen spell introduced in ArM5, p. 160. It is one of the defining spells of the setting.

R: Voice, D: Mom, T: Group

A Communion is most effective if that maximum number of participants take part in it. If the magnitude of the specified spell is M, this implies (M+1) participants. If every magus knows the WC spell at level 10, this should suffice for the casting. The level-limit (the second paragraph in the spell's description) is therefore only relevant if for some reason less magi participate in the casting.

It isn't quite clear whether WC needs to be cast. The spell describes how the specified spell is cast depending on the number of participants, but nowhere is it made clear that participation requires casting the spell. Arguably, however, since it is a spell, participation implies successfully casting the WC spell. In this case, many participants are a down-side as they increase the risk of botching, which in turn may jeapordize the spell casting or even other magi. This risk can be alleviated by mastering the WC, but this requires an investment of even more seasons from all the covenant's magi.

Given enough participants, however, a Communion can be highly effective. It can effectively provide a +2 bonus to the casting total for level 5 spells, a +6 to level 10 spells, +11 to level 15, +16 to level 20, +20 to level 25, +25 to level 30, +30 to level 35, and so on. For high-level spells, then, a Communion can almost add the spell's level to the casting total. This can significantly increase penetration, or allow casting in foreign (usually Dominion) auras.

Given a covenant of 6 magi, each knowing WC to level 10, the Communion can be used to boost a level 30 spell at most. It then provides a +25 bonus. If five members know the WC to level 15 and one to level 25 (a Muto or Vim specialist), which might be more plausible for a "standard" covenant that puts an emphasis on using the WC spell, it can boost a level 50 spell and provides a +41 bonus. A four-magus covenant with this constellation, which is perhaps a more common player-character covenant, can boost a level 40 spell, providing a +30 bonus. While these numbers fall short of the allowed maximum boost, they still allow very considerable boosting of medium-level and combat spells. A covenant is thus very likely to be able to use the WC to significantly increase penetration if needed.

The Mercurian Magic virtue supposedly greatly enhances the use of WC, but its usefulness can be limited. If you rule that the WC need not be cast, then MM is perhaps most useful in that it allows specialists in other Arts to enjoy high levels of WC. The addition of spell mastery to the WC's level is usually marginal. The primary benefit of MM, the reduced vis cost, is actually incompatible with WC, unless all participants practice MM.