Symbiotic Weapons (Items and Prestige Class) [Transfer From Old Forum]

[Proven_Paradox]

BAB = base attack bonus
PrC = Prestige class

Even with a DM deciding whether or not a player will ever be able to have such a weapon, due to the overpoweredness of the class I'd be willing to bet that that would be a "no" about ninety percent of the time. Hence, my suggestion that you look at the Shining Blade.

The basic idea behind the Shining Blade of Heironeous is a warrior that can give temporary powers to his/her weapon a limited number of times per day. For example, at a certain level s/he could make his/her weapon Shocking X times per day for Y rounds, and it would stack with any bonuses the weapon already had and any other bonuses that s/he'd granted it earlier that were still in effect. That PrC was meant to be entered from Paladin, so Charisma determined a lot of those variables. If you choose to go this way with this class, you could have it based on Character/Class levels, perhaps.