Possessed Weapon [Fighter]
Your weapon is possessed by a demonic or other evil entity.
Prerequisites: Must own a weapon of at least masterwork quality, character level, evil alignment
Benefit: Your weapon is possessed by some kind of evil creature. This grants it a variety of benefits.

Choose a weapons you own of at least masterwork quality. This weapon becomes possessed and is henceforth indestructible. If you lose the weapon, you can spend thirty minutes to summon it back to your location.

Further, destroying valuable objects with the weapon can awaken some of its latent magical properties. Every valuable object which you break with the weapon adds the broken object's value to the possessed weapon's, and no magic or devices can restore the broken object to its normal function - it crumbles to harmless dust. By spending an hour attuning your possessed weapon, you can change it to any weapon whose value is no greater than the total value of the possessed weapon. For example, a masterwork greatsword has a value of 350 gold pieces. If you use your possessed greatsword to sunder a greatsword +1, worth 2350 gold pieces, the total value of the possessed greatsword becomes 2700. You could then make the greatsword a +1 weapon, in which case the value of the weapon is still 2700 (which would entitle you to turn it into a composite longbow +1 (Mighty +3) worth 2700 gold pieces, for example).

Destroying valuable creatures doesn't add to the value of the weapon or make those creatures particularly hard to remake. Even though shields are, to an extent, weapons (and you can use most anything as an improvised weapon) the item chosen and the items that it's turned into must be items which are primarily weapons. You can't turn the item into a non-masterwork weapon, nor can you make it into a weapon with limited uses.