[@Doll Maker]

[i][b]Essence Erosion[/b]:Corrosive energies spill fourth from Anasazi’s frail form, coating his surroundings in a thick mist.  Within the fogs domain sorcery’s stranglehold erodes. Spells falter and magic’s destructive capabilities are diminished. Beings of Essence likewise weaken, but are not destroyed. Instead they slowly wither away, ensuring Anasazi’s victory. Of course allies are immune to this effect as is Anasazi himself.[/i]

I'm a little wary of anything that weakens or nullifies powers mainly cause effects that strip someone's ability to perform actions can be found as frustrating and boring.  To allow this power, it needs to be channeled, basically your focus must be to maintain this myst less it quickly dissipates if your concentration is broken.  You can walk whilst it is cast, but not much else.  Additionally, the myst itself cannot hide those within, and if it does, it also obscures their vision as well.  So yes it acts like a very potent shield for essence based effects and spells but it lowers allies accuracy whilst within.

Your character fits the bill as a summoner.  A mage character is something we do not have many of.

However, if you would be so kind, read the rules and make the required change.