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.
Only permanent items (non-charged) items can be created through this method. Items limited in uses/day are fine, as are items with a charged component (a luck blade could be created (the wishes are ‘charged’ and can be used up, but it’s still a +2 short sword that gives a +1 luck bonus and grants good fortune).
Item creation by binding a creature into an item lets you get around some of the prerequisites for creating the item. When creating a magic item by binding you can use the higher of your caster level or the Hit Dice of the creature being bound (a Wiz5 could craft a +3 sword if he binds a 9 HD creature). Spell prerequisites can be met by either your spellcasting abilities or by the abilities (spell-like or supernatural) of a bound creature, or by the nature of the bound creature. A flaming sword could be crafted by a Wiz5 with fireball, by binding a horned devil (fireball spell-like ability) or by binding a fire elemental (creature with the Fire subtype).
How to Bind
This requires the Binder item creation feat.
Binder [Item Creation]
You can bind creatures into magic items on creation.
Benefit: You may bind creatures into items as part of item creation. This can let you work around certain item creation prerequisites as described in Bound Magic Items.
All steps of enchanting the item are done normally (you spend the regular amount of gold and experience points for the item being created) but the powers the bound creature will provide prerequisites for are not active. For instance, +3 holy longsword created by a Wiz7 might be only a +2 longsword until the astral deva is bound.
The creature to be bound must either by willing or helpless. The creature must be ‘killed’ (the willing creature ‘dies’ automatically (cooperatively), the helpless guy can be treated as a coup de grace attack). When this happens, the creature is bound and the process is complete. As far as I can tell, if you have a cooperative or helpless creature, it’s about as good as dead and binding is about the same as killing it. (Though there are other considerations — a bound creature is effectively trapped and not available for resurrection.)