Where Xander summons the impression of earth, and Sven literally brings the fire, Nita focuses directly on the towel fabric itself.

/This is a fortification wizardry; we're going to lend you power, so you'll never have to fear burning to cinders ever again!/ Nita declares, before diving into the more formal language and framework that will allow for such an imbuing of power.

Wizardry is more of a blue light, in contrast to the actual flame around her, but it glows just as brightly with her intent. Now, the fabric can be brought around to understanding their points of view - and it's more than willing to be made impervious to flame!

Or even just resistant.