Just something that bugged me for quite some time, and I couldn't find the proper answer: what happens to Menos and Arrancar after they die?
We've seen that after being lethally cut with Zanpakuto, a standard Hollow is purified and continues to exist as a human soul in Soul Society.
But what of, say, Gillian: they exist as an entity of hundred of souls merged into one. What happens after a Gillian is killed? Do all the souls transcend to Soul Society? Or none? And if so, where do they go? With as with sentient Gillians, Adjuchas and Vasto Lorde, there is a possibility that only the dominant soul transcends death as a Hollow.
But what of Arrancar: considering they are neither Hollow or Shinigami, the aftermath of their deaths are... what? Considering that they are part Shinigami, it would be reasonable to assume that they are unable to go to Soul Society, as Shinigami don't do that. However, as they are Hollow, it would be the only possible thing to do (well that or Hell, but Hell tends not to happen often in universe of Bleach). And if they simply cease to exist (like when killed by Quincy), it would actually make more sense to keep them alive, as the loss of that amount of souls would be cataclysmic. When it comes to Resurrección (as far as I know) Arrancar are temporarily changed back into pure Hollow.
And what happens to Hollows (regardless of their rank or sub-species) when they are killed by a Fullbringer (I'll just assume that Orihime is also a Fullbringer of a sorts): Fullbringer are neither Quncy or Shinigami, so it would be reasonable to assume that they don't destroy the souls, but cannot purify them either due to lack of proper tools.