I'm not in favour of working with Guys, but rather, I prefer to add some flags and vars to the npc class, some movement patterns, and ... a string field to the screen npc list, to allow the questmaking to create livelier towns, with strings attached to npcs, and guys that can move about as in Dragon Quest, or what-have-you.
We have discussed the Z3 sword, but the Z4 shield. What does this need to do? Push enemies with a 'can push' flag? Add a shield lweapon? Allow shields to be equipment items that turn on and off?