[@Artymis]My 'unique' idea is that they're originally two separate forms but combine together once in bankai (which will come later if the rp lasts that long) to form the 'true' entity of the Zanpakuto. Basically two halves of a whole, a ying, and a yang so to speak but they're aware of, and dislike the fact that they are. The true entity being a being called 'The Thunder Emperor' in the visage of a japanese samurai in heavy armor. Of course I'm perfectly willing to dial it down, and just make it two different beings inhabiting their own unique blades.