Item creation in 3e is very abstract. Take a masterwork item, add gold, experience points, and time, and you end up with a magic item. The item creation might involve binding spirits, it might involve empowering the item with planar energy, it could simply enhance the nature of the weapon to make it better at killing, whatever. It’s never actually spelled out, so it could be anything.
I’d like to find a way to allow explicitly binding a creature into an item as part of the enchantment process, and a reason for characters to do so. I think I’ve found an answer I like.