Well, in days of yore, when Carnifex magics still existed, and Lhomarrian mages cast spells today's wizards could only dream about, there was one spell in particular that was created, which served to shift the balance somewhat against the more numerous hordes of the Carnifex of Y'hog.
This spell, link, allowed two or more mentally attuned wizards to pool their magical powers, linking their minds in the process, and thus cast spells with intensities much more powerful than one person alone could handle. This allowed Lhomarrian battle-mages to meld their powers to create fireballs that could devastate entire cities, or even cause earthquakes that could level mountains and hills, and create great canyons.
Since those days, the spell has largely been forgotten. No one in Selhomarr knows of it today, and only among the most powerful wizards of Niscosenia are any copies in existence. In the days after the fall of Lhomarr, Ixion came to his faithful in the Lost Valley colonies, and told them to put aside that spell, for it was too dangerous, and it must not fall into the wrong hands in the dark times ahead. Indeed, he made a pronouncement that day, that:
"There shall come unto you, some day distant, when the stars shall rotate in their circles, until they rest then as they do now in the heavens. When that time comes, a great evil will stalk the lands of your world, and then, my children, shall you need the strength of Lhomarr once more. In the darkest hour, the power of Old Lhomarr shall rise once more, and the light and knowledge of your fair realm shall grace those lands that will think themselves dominant, and the world shall be stronger forevermore. Until the stars do align once more, be faithful, hold the trust, and never let the sacred link fall to those who would do you harm."
So it has been for thousands of years, the wizards of Niscosenia never forgetting their promise to Ixion. One day soon, the astronomers in that nation say, the stars will once more be in alignment. The darkness is at hand.
Link: (9th level)
Range: Touch
Duration: One spell
Effect: Enhances the power of the spell affected by link
This spell allows the caster to pool his or her magical powers with other
magic-users, in order to boost the power of the spell to be cast. A group of
spellcasters pooling their powers in this way is called a ring. The
person initiating the link, and any spellcaster joining the ring, must
know the spell to be affected by the link spell. The maximum number of
people that can join the ring without causing spell failure is equal to
one-third of the Intelligence score of the person casting link. Thus, the
greatest number of people who may participate is six (an Intelligence of 18
divided by three). In the ancient days of Lhomarr's glory, there were tales of
rings composing 10 or more spellcasters, but many people today doubt the truth
of these tales.
To cast link, the leading spellcaster must ensure that everyone participating in the ring holds hands, so that they form a circle. The leader then recites the link spell, and every participant is connected telepathically to each other, and is surrounded by a pale blue glow. Once the link is established, the ring can then cast the spell to be enhanced in the next round. This link spell is of such power that it negates the need for gestures when casting the spell to be enhanced.
When the affected spell is cast, the enhancement is instantaneous. The enhancement depends on the number of people in a ring. For every additional spellcaster in the ring, the spell's duration, range, area or effect, and damage (where applicable) are multiplied by the number of participants. Instantaneous spells, such as fireball, are not affected in terms of duration, but the damage, area of effect, and range are.
For example, a damage of 10d6 for an offensive spell, cast by a ring of three wizards, would have a damage of 30d6. If the range was 100 feet, this would increase to 300 feet. If the area of effect was 50 feet cubed, this would increase to 150 feet cubed. DMs should note that this powerful spell is very rare, and in any case must be cast before the enhanced spell. Likewise, participants in a ring are totally oblivious to the world around them, and anyone attacking a ring should ignore any armour class bonuses that the defenders may possess.
Finally, remember that you should account, in determining initial spell
damage, range, and so on, for the level of the person who casts link.
Just as the Intelligence of the caster determines how many magic-users can join
the ring, so he or she determines the initial characteristics of the enhanced
spell. Thus, if the primary caster can cast a 9d6 fireball then all subsequent
multiplying works off of this number, even if someone else in the ring could
cast it as a 10d6 spell.