Is there a way to create an item that you can attach to another item (in this case a weapon) to give it additional powers? What I'd like to create is a "Hilt-guard of Harmonizing", which can be attached to any light blade to give that weapon the Harmonizing power (custom power I "borrowed" from 3.5). I'm just not sure how to "link" one item to another. I'm looking at the Wayfinder/Ioun Stone relationship as a possible model (i.e. make the hiltguard a container you can put a light blade into), but I'm not clear how to tell what's being held by the container to affect that item's properties.
Is this a reasonable approach, or is there a better way? Or should I just tell my player "add the Harmonizing power to your rapier".
Is this a reasonable approach, or is there a better way? Or should I just tell my player "add the Harmonizing power to your rapier".