What happened to Yachiru?
Yachiru has disappeared. The last time we saw her was while Kenpachi was fighting Gremmy - about the same time as Kenpachi released his zanpakuto, Yachiru thought back to the day they met. And then after the fight, nothing was left of Yachiru but her clothes and her lieutenant’s badge. Kenpachi freaked out, and has been trying to find her, but so far, that hasn’t happened. So let’s see if I can come up with a whole ten theories for what might have happened to Yachiru!
1. She is Kenpachi’s zanpakuto.
This is by far the most popular theory. The timing works great: Kenpachi calls his zanpakuto’s name, Yachiru flashes back to when they first met and Kenpachi gave her name, and then Yachiru is gone. We even have foreshadowing, since Tite Kubo likes to foreshadow through doublets - just as Yumichika using the wrong name for his zanpakuto foreshadowed the revelation that Renji was too, so Starrk having a small child as his weapon might foreshadow the same being true of Kenpachi and Yachiru. And let’s not forget how Isane commented that Yachiru’s own zanpakuto was unlike anything she’d ever seen before - perhaps because it wasn’t a real zanpakuto. So under this theory, Yachiru isn’t gone - she’s simply reverted to her true state as Kenpachi’s weapon, now that Kenpachi knows her real name.
How likely this is: I’d be shocked if this *wasn’t* true, to be honest.
There is one Quincy we know of who likes to take dead / near-dead shinigami and change their clothing, and that’s Giselle. Hitsugaya showed up as a zombie wearing a Quincy uniform, so maybe the same thing is going to happen to Yachiru.
How likely this is: Eh. I feel like the zombie portion of the manga is probably over, but who knows. Giselle is still around.
Dead-dead, I mean, not Giselle-dead. Perhaps a as yet unrevealed attacker came upon Yachiru, killed her, and stole her body. I don’t know why, and I hope this isn’t true, because if so it’s super disturbing. Or maybe her body vanished, as when Aizen was killing people for the hogyoku. Which would somehow be less disturbing.
How likely this is: Unlikely, given that it would be a lot of buildup for a disappointing and upsetting reveal.
4. Kurotsuchi took Yachiru.
Kurotsuchi gathered up all the zombies, and we know he’s cool with using pretty much anything as a research subject. And if Yachiru’s zanpakuto is truly unique, then perhaps Kurotsuchi would be interested in her powers. But seriously? All these are super disturbing because her uniform was left behind, so again, let’s go with this not being true.
How likely this is: Again, pretty unlikely I would think.
5. Yachiru is doing her own thing.
So far I’ve been assuming that Yachiru had no control over what happened to her, but maybe that’s not so. Maybe Yachiru is on a mission of her own, changed clothes so as to be incognito, and is going to show up when it’s time to do whatever she’s planning.
How likely this is: I could actually see this being true. Yachiru certainly has secrets, and it’s not a given that they are Kenpachi related.
6. Yachiru is working for Urahara.
If Yachiru left of her own accord and changed into some sort of costume, then it is also possible she is doing so because Urahara asked her to. If anyone is manipulating people behind the scenes at this point, it’s Urahara.
How likely this is: Kinda unlikely, I think, since it seems like Yachiru would have shown up by now if this were the case.
This is similar to the zanpakuto-theory, but it’s possible that Yachiru changed form in some way without it being related to her being Kenpachi’s zanpakuto. Maybe Yachiru changed into an adult (and hence needed a new uniform) - Tite Kubo loves that trick. Maybe Yachiru is a cat-person, like Yoruichi. Maybe Yachiru is a werewolf like Komamura. Regardless of her shape change, it would provide a less creepy explanation for her left-behind uniform.
How likely this is: If the zanpakuto thing isn’t true, and Yachiru doesn’t have a plan of her own, then I guess I would go with this as my #3 theory.
8. Yachiru is with Mashiro.
All I’m saying is that they both seem to be missing. Highly suspicious, that.
How likely this is: Probably unlikely, but seriously where IS Mashiro??
9. Yachiru knows how to help the Soul King.
Ukitake tried to save the Soul King. That doesn’t seem to have worked. Presumably something else needs to happen to prevent, you know, the universe being destroyed. Perhaps Yachiru is going to show up with some sort of way to save the Soul King?
How likely this is: Eh, it’ll probably be Ichigo who saves the day somehow.
10. Yachiru is a piece of the Soul King.
Ukitake turned himself into the Soul King’s arm, since apparently that arm ended up in the Rukongai or something. And the last time we saw the Soul King, he was pretty much just a torso. That would seem to imply that there are other limbs around. Perhaps Yachiru is one of those?
How likely this is: I doubt it, but I think it would be cool.