[Galleon Rock]

Jace assumes the normal stance of a magic user in situations like this.
He hops off the bear, takes cover behind her, and puts up his force-shield ring above him and Zebes as an umbrella. Once their volley is over he jumps out, assumes Doctor Strange's rock-horns pose Dammit Zebes that's not what it is!, and sends a number of large lightning bolts to all of the skeletons within 30 feet of him.

Hopefully he doesn't need to do this more than once a day because he actually can't.

Meanwhile, Zebes turns invisible and tries to sneak around the battlefield to the necromancer.