You're back! Yay!!! Okairi na sai, senpai. It really is good to have you back and healthy.
Polls 'Pinion.
I have what you would call a plethora of ideas as to who the 'real enemy' could be so I choose to not bother declaring my thoughts on the issue, save that we might just find that Urahara and Yoruichi have something to do with it.
"Rukia, Riruka, where art thou be?"
The concept of sharing powers ties in well with the entire Bleach story considering that the very first part of the first arc featured Rukia attempting to give Ichigo some of her Shinigami powers (which was a failure as Ichigo ended up with every last drop of it). And how this was even the reason she was slated for execution...sorry, 'xcution'

. So, we now know that it is not only possible for a Shinigami to share their powers with a human being but with a fullbringer as well. Oh, and this also explains how and why the captains were able to transfer their reiatsu to that sword (I didn't get it before). I doubt this would be last time we hear of this sharing galore.
Concerning Riruka, I agree with what you opined. What is the one thing Riruka now has in common with the Hogyouku? They have both been stored in Rukia. Maybe she found Rukia cute (she actually is kinda cute, that Rukia

; could be why Urahara chose her as Hogyouku Central) and then stored herself in her which should make for a very interesting show. But why does Rukia end up being the vessel of choice for unsavoury entities? Perhaps there is a reason for this which could play into the real enemy situation (Urahara, anyone?). Or it could simply be that Kubo secretly hates Rukia for being so cute

.
The True Kuchiki & Tsuki.
In response to your head-spinner, Hitsugaya definitely went for rank first. I mean, it's Hitsugaya we're talking about

.
It may not have been that Byakuya felt a closer bond to Ichigo as did Inoue and Chad, but that he was sticking to the orders of Genryussai that the captains were to help Ichigo at all cost (hope this is correct, cos I can't really recall Yama's true words.) If this was the case then it would seem that Tsuki did not really understand Byakuya's heart as to where his head would lie in a conflict-of-interest situation. He probably didn't recall that Byakuya was willing to personally behead his kid sister once the order had been given (and that he even lead the expedition that captured her in the real world). So, in other words, stick to all orders and relationships be damned. Either way, I'm glad that prissy, bookmark-totting thug is dead. (I now also understand how the petals worked

).
Aizen's Protege, Aizen's Paradox.
Remember when Aizen tried covering his tracks by blaming Hitsugaya for his death? Notice how Kuugo is about to do some blaming of his own? Ok, I know I'm ignoring a pile of differences, but they do share that in common

.
Now, remember when Aizen confessed that he had planned all of Ichigo's fights, and in response Ichigo called him a liar? And Aizen tells him that though he called him a liar he was willing to believe an earlier staement he made? This is what I have dubbed Aizen's Paradox.
Aizen's Paradox:
How do you know when a liar is lying when he has not expressly told you that he is lying especially when he is the only witness? (Head-spinner extraordinaire


)
So how do we know that what Kuugo is telling Ichigo now is the truth? Just saying

. But I can relate to how a fullbringer's ability fades after their death cos the same thing works for kidou (I think).
Back to the protege, Kuugo is not just a jerk. He's the jerk who intiaited the whole shebang according to the tale Kuugo told under the rain.
"In The End..."
I enjoyed this chapter as well and I hope the plot progresses appreciably in the next chapter cos this cliff hanger is killing me!
Once more, welcome back to the world of the healthy ones and we hope to have you for good


. Thanks alot for the review. Till next time.