A.N. This is the prelude to a fic that presents a different look at the zanpakutou spirits. Mostly however it is just target practice for your flames.
Wind, Water, Earth, Fire,
These are the primal forces that shape our world, our, universe, but not just this one. There have been countless universes in the past and there will be countless more in the future. When a universe dies it is not the end for it. At the Final Hour of the last Universe the last four mages led the fight for the right of their Universe to be allowed to survive. Valiantly they, their shikigami, and their vassals tried to defeat Kronos, The Lord as he began to unravel the seams of their reality. Taking pity on them Gaia, The Lady took them within her arms, protecting them but also forcing them to sleep, there they remained floating amongst the ruins of their past. When at last the time came to remake existence. Gaia remembering their bravery decided that they shall be given a second chance at life. On the surface this seemed like exactly what they wanted, but the Four sensed that there was more to it than this. They were correct, this was not their world, they had no place here, no form unless given one, they who had once ruled entire worlds had been reduced to the level of a shikigami, now called zanpakutou. The Four Great Mages became The Four Great Spirits, each bound to the form that their shikigami had taken, given it's powers and sealed away.