Sorry, Psyren, I didn't think you wanted the full block quote. And thanks Lilet for reminding me. The relevant bit of commentary begins on the page facing strip 412...
Spoiler
Show
"I then [after clearly establishing each character's location] made certain to isolate characters who could change the intended outcome of events [of the Battle of Azure City] away from the action - and I needed to establish that I had done so before the events in question transpired. That's why the war was by far the most well-planned story I have yet written for OOTS, with full scripts prepared for almost the entire war before it began.
"One of the prime offenders in this area was Vaarsuvius. The unfortunate truth is that a high-level D&D wizard is enormously powerful and can manage effects that would have nullified most of the plot twists I had planned. A wizard could have blasted Xykon from afar or given Roy a flying spell (or at least a feather fall), all of which would have derailed my planned death scene. If I had created the physics of the OOTS world from scratch, I would have simply not given Vaarsuvius any capabilities that could interfere with the plot, but one of the great writing obstacles I face is that it is the game rules that set the boundaries of my characters' power. My readers know what a wizard of V's level should be able to pull off, and when he/she fails to display such powers in a do-or-die situation, they (rightly) cry foul. And so I wanted V out of the way of the others. I still wanted him/her to get the chance to unleash his/her magic on the battlefield to full effect - just, you know, over there. The opening salvo (the titanium elementals) therefore effectively separates V from the rest of the party, and they remain apart for the rest of the battle."
Whether the objective that a character that is separated from the group for the sake of preserving the plot still gets to affect the story in some way has been preserved is, in my view, debatable.