Lilygod Wynter - Tumblr Posts

Potential.

Every dead soul was once a living organism. Plants, trees, animals and people in Soul Society were all once alive. Humans in particular were created in such a way that their potential spanned out before them, if only they had the courage and power to grasp it.

Upon death, a human soul can go one of two ways: locking away their rationality, decision-making capacity and ability to say no, stop, enough, for the gain of power, the retention of growth and evolution; or, excising their potential, their ability for growth and power and ability to become more in such a way that allows them to keep their mind and individual thoughts.

According to shinigami, who in many ways don't understand or even know the meaning of potential, this is the difference between a soul that passes on, or a soul that hollowfies.

The true difference in them, is that a "plus" soul or Shinigami has cut out and/or eroded away their power of progress, in a way that is subtle enough not to be noticed; but, in hindsight or from the viewpoint of a foreign intelligent being, is all too clear and unsettling. A Hollow, meanwhile, has changes that are so obvious as to mark them as an entirely different species, even though they aren't; they trade their higher minds - temporarily - to keep the ability to grow and change and evolve to greater strengths and appearances. And the stronger they get, the closer a resemblance they achieve to their original form: the human one. This, after all, is how Vasto Lorde are born, and they are frighteningly similar to humans in so many ways.

Of the two types of soul, Hollows are the ones who, in the end, have the opportunity to truly become "human" again - albeit, without a physical body.

Shinigami, meanwhile, are stuck; their souls find comfort, an equilibrium, and simply stop there. They have a set amount of power, conforming most often in a 100:1 ratio to what they had as humans (and even that only partially accessible without training), and no more than this. By cutting off their growth capacity, so they have limited themselves to remaining as a fraction or less of what they once were, or could have become.

When attempting to create a hybrid, a Vizard, the process was likened by Aizen to knocking down the barriers between Shinigami power and Hollow power. I, however, hold with a... mildly different hypothesis.

I suspect that Aizen may simply have returned to those Shinigami their own potential for growth.