One thing to keep in mind is the combat system basically just makes sprites run around and perform various animations, cast spells, and use items. As long as you insure these sprites won't do your PC any harm (give them a zero dexterity, or, to be sure, give them a weapon with a "hit condition" that is impossible to satisfy, like "if player gold is greater than player gold"), then these spells, items, and animations can be used for anything. An example:
Give an NPC the "ranged fighter" behavior. Make his ranged attack animation a friendly wave, attach a sound ("Hi neighbor!") and give him a low LOS. The NPC will say hello when your PC nears, and return to his business when the PC leaves his LOS.
If you were looking more along the lines for an alternative to attacking and defending for the attack and defend functions, how about dancing? The defend button can create a looping animation, and the attack button can switch up the dance by changing the player map icon. Heh. That's a good idea.
myshkyn
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"I'll give the fans just what they want, and nothing else at all."