The Real Juha defeated Kenpachi NOT Royd
I think this is the most likely scenario to what happened with Kenpachi and I think there's plenty of evidence for it.
We see that after Bach decides to go invade SS there's an announcement telling
all the SR to assemble at the Sun Gate:
We even see the SR going towards the Sun Gate without Bach. Royd is a SR so he must have gone to the Sun Gate as well as the announcement said nothing about signalling him out and we know that he wasn't with Bach already because Bach was clearly alone in his throne room when he decided to head out to invade SS the previous chapter.
Next we see Juha arrive in SS and create these pillars of Blue Reishi fire. This is the real Juha. All the SR were ordered to assemble at the Sun Gate and Juha was not seen going with them to the Sun Gate so the most logical answer is that Juha was to go to SS alone and create the pillars of Blue Reishi fire which would act as 'exits' to the Sun Gate for the SR (it would make sense for exits of the Sun Gate to be fire itself). This would make sense as Juha is the only Quincy so far who has shown to have the ability to create pillars of reishi fire.
Next time we see Juha with Haschwalt right under him facing the 13th Division:
So we know for a certain amount of time Juha was with Haschwalt. What we need to do is to pinpoint exactly when Juha left Haschwalt for Aizen and had Royd replace him.
Next time we see Bach is right after Byakuya is defeated by As Nodt:
I think the way Bach interacts with Bishie gives away that he's the real Bach. Royd doesn't make the most sense in terms of context. I mean everyone around them is dead so why would Royd be pretending to be Bach at that point in time? Makes more sense if it was the real Bach.
Next we see Juha grabbing Kenpachi by the throat:
It seems that Bach has some sort of personal interest in the SWP as he planned to recruit both Ichigo and Aizen. He also interacted with them personally. It would be strange for him to have Royd deal with Kenpachi. It would make more sense if he dealt with Kenpachi himself. I personally believing he plans on using the 5 SWP to combat the RG but that's another theory. I also think that perhaps Bach tried to recruit Kenpachi off-screen and maybe we'll be seeing that in a future Kenpachi flashback.
Now Bach had dealt with Kenpachi and he knew that Kirge had Ichigo hostage so he could go deal with him when he returned to HQ. All that was left was Aizen but suddenly Yama appears to block his way.
While Bach is confronted by Yama we see this strange sneak attack on Yama by 3 SR:
The funny thing about this attack is that it's so stupid its ridiculous. The 3 SR don't try to use Vollstanding or their abilities. As Nodt doesn't even try to use his fear arrows. Sure the SR are cocky but they must know Yama's strength and must realise that simply jumping on him is suicide. At least Driscoll had a plan. Driscoll probably heard about how Sasakaibe's Bankai had left a permanent scar on Yama so he thought Sasakaibe's Bankai was OP and he could kill Yama with Sasakaibe's Bankai. However Sasakaibe's Bankai was weaker in his hands. However these 3 SR seemed to have no plan. Instead they just jumped on Yama out of nowhere which is beyond stupid.
I think this is when the switch between Juha and Royd took place.
What many people forget is that the sneak attack forced Yama to divert his attention away from Juha. Yama didn't want to kill the 3 SR because it would be dishonourable to kill loyal subordinates in front of their tyrannical ruler. So Yama defended himself but he took care to make sure the SR were not killed. You can even see this in the following pages:
Yama even has his head turned around out of concern so it makes sense for him to temporarily not pay attention to Bach. Plus what people need to realise is that
Quincies are humans. Sure Bach might be a former Shinigami but judging by Royd's flashback I'd say the safest assumption to make is that all the other Quincies are just regular humans. Let's recall what Bach said about Yama and humans:
Bach outright states that Yama was overprotective of humans and that's what made him weak. The 3 SR intentionally or unintentionally used this to their advantage. They knew Yama would be overprotective of humans so he would take special care to not kill them and thus lose some of his attention against Bach. This is why judging time based on manga pages is a bad idea. For all we may know, Yama might have been staring at those 3 SR burning for 5 minutes because he felt pity for them. This gives ample opportunity for the switch to take place. It also explains why the 3 SR just randomly jumped on Yama like that.
Another factor to consider is
why would Juha pick Royd out of Royd and Loyd to impersonate him? Let's look at the pros and cons:
Loyd - can replicate power and can obviously last longer in a fight against Yama
Royd - cannot replicate power and needs to rely on his own to survive against Yama.
- pries into the personal memory of those who he copies.
- is a very good actor.
The only advantage Royd had was his acting skills. Other than that not only was he not as powerful but he also invaded Bach's privacy by copying his memories. He would know the deepest darkest secrets of Bach's life. Loyd doesn't do that so why pick Royd? The answer is obvious
the original plan was to use Loyd but use Royd in case Loyd is killed. We see Kenpachi rushing to Bach and as he does he killed Quincy nearby and this included Loyd. As Loyd was killed, Royd realised the duty was on him then. That's why Juha said Royd did well when he returned from Muken (because it was actually supposed to be his brother's job) but then killed him (as Royd pried into his personal memories).
IMO the events went something like this:
1. Royd, As Nodt, Nanana and Buzzbee meet up after their battles.
2. Royd is aware that Bach wants to meet and try to recruit the SWP asap so in case Yama gets in the way and his brother is killed then he's supposed to fill in Bach's role.
3. The 4 SR sense Loyd dying they rush to him to see how Bach's doing.
4. The 4 SR arrive too late to the scene and see Yama already confronting Bach. They quickly think up a plan to divert Yama's attention away so Bach will still get his opportunity to try and recruit Aizen.
5. As Nodt, Buzzbee and Nanana all jump on Yama and while Yama has his back turned Royd comes up to the real Juha and tells him that he's ready to switch places with him and that Juha can go see Aizen now.
6. Royd takes on Juha's appearance and calls the 3 SR 'foolish people' the moment real Bach vanishes from sight (maybe via the Shadow technique).
The next thing that needs to be understand in terms of context are this pages here:
Over here I've seen a lot of people interpret Bach's lines to mean that he has been talking with Aizen ever since he entered SS but I honestly don't think that's the case when you apply the context behind the situation. The only reason Yama seemed to ask Bach is because he had discovered that Bach had left an imposter in his place:
So when Yama says 'What have you been doing all this time?' he means 'What have you been doing all this time while you had an imposter take your place?'. The thing that people need to realise is that
Yama doesn't necessarily know when the switch took place however
Bach does know when he switched places with Royd. Thus Bach is answering from his own perspective. He's saying that during Yama's battle with Royd he has been talking with Aizen. After all Bach isn't a courteous guy so why would he waste time trying to correct Yama and tell him exactly when the switch took place? Do you seriously think Bach is going to say, 'By the way Shigekuni while those 3 SR jumped on you I switched places with Royd and went to see Sosuke Aizen. Before then I came and created the pillars of blue reishi fire which summoned the SR here and I watched as Haschwalt and I murdered the 13th Division members'. Why would bach bother being so courteous to Yama? It's quite unlike him so yeah I'm pretty sure when the real Bach comes back and says he has been talking to Aizen the whole time, he meant during the fight between Yama and Royd (which was an answer from his own perspective).
The reason why Juha was so desperate to try and deal with the SWP asap is stated here:
Juha knew that after he defeated Yama he pretty much defeated the rest of the Gotei 13 because their morale would be lost after the loss of their leader. However
what Bach was worried about was the RG. It seems that Bach didn't seem to know much about the RG. All he seems to know is that they would come help SS after the Gotei 13 was defeated. It seems he wants to retreat and reassemble because he doesn't seem to know much about them and whats to take a safe approach to defeating them.
Like Bach didn't seem to know how
long it would take for the RG to arrive in SS. They might appear in 5 minutes or 5 hours. The RG > Gotei 13 so even with Yama's Bankai Bach knew he might end up losing to them so he decides to have his army retreat. He doesn't even bother trying to make sure all the rest of the Captains are dead. He just wants to retreat asap.
It's only when Ichigo arrives that he decides to stay a bit longer but that is only to capture him and take him away as Bach says so here:
The thing is that even though Bach is fighting Ichigo
he's still in a big hurry to get out of SS. He tells Ichigo a bit about his origins but when Ichigo tries to question him further, Bach brushes him off and says he'll tell him when he takes him back to VR HQ. It really seems like Bach fears the RG that he wants to leave SS asap so he doesn't have to face them now. But the fact that he stopped to try and get Ichigo implies just how desperate Bach is to recruit these SWP (which gives some sustenance to my theory that Bach plans to use the 5 SWP to combate the 5 RG).
This is why Bach went to go see Aizen asap. This is why Bach went to Aizen before killing Yama.
Because Bach fears the RG. He probably doesn't know much about them but the little knowledge he does have tells him that the RG arrive when the Gotei 13 is defeated (which would essentially mean when Yama is defeated) however the timing of their arrival and such may not be to his knowledge so it would make sense for Bach to not want to take any risks. Suppose if Bach fought and killed Yama when he first turned up without using Royd, then Bach would fear that he won't have enough time to talk to Aizen because he probably won't know how quick the RG would be in arriving to save SS (and we all sure know Aizen likes to talk a lot lol).
Above all this I just find Royd defeating Kenpachi to be illogical. You're telling me that Royd hurt eyepatchless Kenpachi so bad that he left him in a state where Kenpachi barely escaped death and is unlikely to even wake up or even resume his duties as a Captain due to seriousness of his wounds? Royd could do all of this when he can't copy powers while his brother who could copy powers was owned by Kenpachi? I don't find this plausible.
Above all this I don't find the power that Royd displayed to be impressive enough to take credit for Kenpachi's defeat. What Royd basically had was speed. We barely saw much of an offence from him. When Yama was in Bankai Royd was pretty much running away from him for the entire battle. I've heard some people say Royd could fight on par with Yama in his Shikai but I disagree because we barely saw Royd do any fighting at all. All we saw was Yama create some fire and Royd created an explosion by striking his swird with Yamas. The main thing people need to realise is that Yama didn't give his all when he went Shikai against Royd. Yama was very angry and just wanted Royd to draw his sword so he could hurry up and kill him as brutally as possible as he says so here himself:
So Yama pretty much just wanted to bait Royd into drawing his sword so he could give him a humiliating defeat by killing him with his Bankai. In a way Yama was arrogant. He had no strong reason to go Bankai. His Shikai could do so much more but Yama refused to do so opting instead to give into his anger. Even Royd is surprised that Yama goes Bankai asap. But yeah that's another story.
So yeah using all the information available I think the most logical answer is that the real Juha defeated Kenpachi and not Royd.