Trollslayers - Ritual magic (part 1)

As mentioned here, magic in Trollslayers is divided into two types, Sorcery and Ritual Magic.  Ritual Magic is slower, but usually a bit easier to work with, and requires less energy to enact.

When making a Ritual Magic roll, for every point that the spellcaster's roll exceeds the target number, the Essence cost is reduced by one point.  No matter how well the roll is made, a minimum of one point of Essence must still be expended on any given spell. 

Some rituals allow than one person can work together to combine their efforts.  Not only can different people pool their Essence together, as they are able, to enact a certain ritual, but multiple people working together may also give a bonus to the spellcasting roll (the roll is made by the person leading the ritual, referred to as the 'lead caster').  Note that those assisting in a ritual need not necessarily know the spell in question, or even be aware that they are aiding in the casting of a spell (this is the basis for various temple rites).  The bonus gained by multiple participants is equal to the cube root of the number of people participating in the ritual, round down.  For those who are mathaphobic or just prefer tables, this translates as follows:

Participants     Bonus
2-7                +1
8-26               +2
27-63              +3
64-124             +4
125-215            +5

And so forth.  Note that the bonus for multiple participants in a ritual cannot exceed the lead caster's combined Ritual Magic skill and PRE attribute bonus.