Give her a sporting chance

"What's your fetish, Kalli?" you say.

She eyes you askance. "Paper."

"Great! Get this girl some paper, we'll have a proper mage's duel."

"You sure about that, Raider?" says Destra.

"Sure I'm sure! It's only proper to give a lady a chance to defend her modesty. Besides, it's more fun."

The Raider's Girls voice their agreement and produce a stack of pages, which they pass off to Kalli. The elf hefts them experimentally, and immediately lets one burn away in her grasp to feed her magic.

"We'll start on the count of three," you say, ignoring the fact that she has already started. "One..."

Kalli lets more pages burn away, gathering up their power in her free hand. It looks like she's getting ready to hit you with something hard.

"Two..."

She pulls back her hand, getting ready to release.

"Three!"

You realize at the last second that you're fresh out of panties to fuel your own magic. You reach for the nearest pair, the one occupied by the lovely Ilsa. She gives a yelp as you take her by the front of the elastic band and pull. The pink fabric rips away, leaving the robust girl covering her crotch with both hands and going up on one foot in a classic "oh, no! I'm naked!" pose.

"He raided me first!" she says. "I win!"

"Hey, the bet was about who he strips naked first!" says Destra. "And you're not naked!"

You've got Ilsa's panties in hand, burning away between your fingers. This will be enough to power one good attack. Now you just need to pick a fun way to get the elf chick's clothes off.