Revising...
Elemental Transubstantiation (Su): Once per day an elemaster can  transubstantiate all material objects and corporeal creatures in an area  of up to 100 5-ft. squares that is within a range of 1000 ft. The  affected area can be any shape. The elemaster can affect an area of any  shape it wishes and exclude creatures within the affected area from the  transubstantiation effect. All affected targets must succeed at a DC X  Fort? or be transformed into elemental substances, the effects depend on  the elemaster's intentions. Creatures that have the same elemental type  as the elemaster are not affected by its transubstantiation; targets  with no material substance are also unaffected, such as incorporeal  creatures or objects of force such as an 
unseen servant.
 
If the elemaster wishes destruction, the target will instantly evaporate/crumble into gravel/burn to ashes/melt into puddles [
delete as appropriate].  The transformed residue of creatures destroyed by elemental  transubstantiation are not the remains of a living creature and can not  be used for 
raise dead or 
resurrection spells. A 
miracle, 
true resurrection or 
wish spell is necessary to bring back to life a creature destroyed by this transformation.
 
Alternatively, the elemaster can transform material objects or creatures instead of destroying them, as described below. Transformed creatures and objects can be returned to their former state by a 
polymorph any object, 
wish, or 
miracle  spell, although only a single creature or object will be affected per  spell, or only part of a structure (up to a 40 ft. cube) if the  transformed object is particularly large. 
 
Transformed creatures become beings of elemental substance. Their type   changes to elemental (if their intelligence is 2 or less) or outsider   (if their intelligence is 3 or higher) and they gain the same subtype as   the elemaster. They also gain a fly (perfect)/burrow/swim [
delete as appropriate]   speed equal to their fastest speed. Note that these transformed   creatures are now susceptible to the elemasters' master elemental power   (see  below).
 
Transformed objects in the area  can be used to form a structure of any shape the elemaster desires, the structure resembles a 
permanent solid fog surrounded by a 
permanent wind wall/a double strength 
wall of iron/a 
permanent solid fog surrounded by a 
permanent wall of fire/a double strength and double damage 
permanent wall of ice [
delete as appropriate], and have Y hp per 5-ft. square. Treat this structure as a permanent magic item, it is not affected by 
dispel magic or 
break enchantment  and is immune to effects of the elemaster's type. It takes a mage's  disjunction spell or more powerful abjuration to destroy the structure  (which is CL 84 and has a +Y on all its saves).