Magic:Elemental Swarm

Conjuration
Level: Drd 9
Innate Level: 9
Component(s): V, S
Casting Time: 1 Action
Range: Medium
Target: Point
Duration: 24 Hours
Counter(s): Dismissal
Saving Throw: None
Spell Resistance: No
Metamagic: Quicken, Extend, Silent, Still
Energy Substitution: No

The caster summons a 21 HD air elemental to act as a loyal servant until it dies or until the spell expires. If the air elemental dies before the spell ends, a 21 HD water elemental is automatically summoned to replace it.
This process continues with an earth and fire elemental until the spell expires. After the fire elemental, no more are summoned.