Board Thread:General Discussion/@comment-25093611-20160418185713/@comment-25093611-20160507143455

^i would think that this is the case, afterall kido seems like a really powerful art once mastered, way more powerful than the relying on swords who mostly only reach shikai for 99.99% of the shinigami :/

this would mean that the zanpakuto got created because the shinigami themselfes caused a imbalance of souls :)

but the reiatsu theory is also a possibility (but than it creates the question: how was ichigo able to purify souls despite having quincy reiatsu too?)