Spiritual Wrath

This powerful cooperative spell is rarely invoked since it requires the concerted effort of six or more high-level priests. The casting effort severely weakens the priests, discouraging casual use of this spell.
To cast the spell, six or more priests must be within a 15-foot radius. Each priest must cast spiritual wrath at the same time. Before beginning the spell, the priests must decide upon the area of effect. The spell causes 10d6 +1d6 points of damage per priest casting the spell. (The minimum damage, therefore, is 16d6.) Creatures within the area of effect are allowed a saving throw vs. spell to reduce the damage to half.
The spell strikes as a great wave of force that descends from the sky. Small objects must save vs. crushing blow. Structures suffer damage as if hit by a heavy catapult (2d12). The force of this spell often raises a great cloud of dirt and dust, obscuring the area for 1d4 +1 rounds.
The spell's area of effect is determined by the number of casters. Each priest contributes 10 feet to the radius of the spell. Six casters would create a spell with a radius of 60 feet. No more than twelve casters can cooperate to cast this spell (maximum of 22d6 damage and a 120-foot radius area of effect). This converts to an 8-inch circle in the BATTLESYSTEM rules ground scale.
The spell is difficult to cast, physically taxing the spellcasters so much that each caster suffers 3d10 points of damage from the effort. There is no saving throw allowed to avoid this damage.

[Tome of Magic]

Sphere: Combat
(Invocation)
Level: 6
Cooperative

Range: 300 yards
Components: V, S
Duration: Instantaneous
Casting Time: 1 turn
Area of Effect: Special
Saving Throw: 1/2