User blog comment:Silver-Haired Seireitou/Sake Time with Sei - Shinigami and Hollows, Thousands of Years of War/@comment-18812574-20140424230811

Wow, the idea of an actual war between the Shinigami and Hollow is... very attractive, to say the least. I can see why you were drawn to the idea. I like Z's answer, but I have personally always thought of it more like an hour glass as opposed to a washing machine. Probably because of the visual analogy that they used in one episode.... no me recuerdo, though. I've sort of always wondered what happens to the souls that get devoured by the Hollows. But I guess that's it... they just get devoured and eventually converted into the energy (reishi) of the Hollow's body. In that case, there would be an obvious problem of imbalance. However, don't forget that new souls can be born into the Soul Society as well, not just reincarnated souls.

1. Anyway, I don't know how well a Hollow army would work. The Adjuchas have been shown to weild some power over inferior ranking Hollows, and have often comanded them to do their bidding. (Gran Fisher and the Forest, most notably.) It would be interesting to see how a rigid hierarchy such as the one Aizen set up would operate if run solely by Hollows, and we never really got to see the full extent of Barragan's "Kingdom," so there's that too. I hate the idea of Arrancar being ruled by Quincy, just to throw in there. I'm sure they would have enough organization to put up some formeralized resistance. (Maybe not so soon after getting wiped out in the Fake Karakura and preceding arcs, but still.) As a side note, the way Harribel interacted with her subordinates can also be used as an example.

2. Probably because of what Z said, again. Involving the Soul King. As far as I know, that was one of the more main reasons for founding the Gotei 13. Course, now they're mostly concerned with self-preservation and the whole "I'm a Death God here to take your soul" aspect has been dropped, imo, sadly.

3. Good question. I was going to say an outright "no," since they seem to have no control over what they become. Look at Nel and her friends. They had the choice to side with Ichigo and fight against Aizen. But then look at Ichigo's Hollow. (While it was still a Hollow.) It was always potrayed as negative and "evil." The threat that kept wanting to take control. But then, you have to look at the ying vs yang thing. If Shinigami are the positive, the Hollow should be the negative. But there is so much gray on both sides... I think it's mostly safe to say that the Hollow are mostly considered evil just because of the fact that they have to cannabalize/kill/eat/whatever to survive (well.) Humans and Soul Reapers, on the other hand, don't have to kill stuff to get stronger.