This is something I have been thinking for a while. Why exactly was ikkaku left behind when the royal guard came? Ikkaku is a bankai user and SS is in a desperate situation. More so, Nimaiya is intimately familiar with the zampakuto of all shinigami apparently. Ichigo did not even have an asauchi and NImaiya still knew perfectly well what was going on with him. It seems like a complete waste to leave behind a bankai user that could actually add to the battle given their current desperate situation.
More so, to add a little more context, isn't it weird that Ikkaku's bankai was so inherently fragile? When we first saw it Eduardo suggested that the inherent fragily behind it was due to the overwhelming power it was releasing. However under that logic ikkaku's bankai has the very distinct quality of being fragile, it is an inherent characteristic of it. That scenario has the implication that ikkaku's bankai would always invariably be a one time event as the end result would necessarily have to be it breaking after using it.
Now, does it add up? Does it make sense that ikkaku's bankai was meant to be used only once and then disappearing if we consider that broken bankai can't be fixed normally? I am thinking that there is something else going on here. I simply don't see how it makes sense for the royals to have left ikkaku behind when SS is so desperately looking for assets. It is entirely possible Nimaiya saw ikkaku's attitude towards his bankai and simply said, "well, this is a lost cause if I ever saw one" however does it make sense to not even test whether he deserves to get his bankai fixed?
So that gets us to the next point, what if his bankai does not need fixing? Nimaiya did not take ikkaku back because there wasn't a need to. Ikkaku's bankai might actually be inherently fragile and based on what we saw taking damage might actually make it stronger so perhaps if taking damage was such an intrinsically important part to it then it must mean there should be some mechanism that allows the bankai in question to be more than a one trick wonder. So perhaps ikkaku's bankai can actually revert to some form which would allow him to use it in battle. Perhaps it did come with an ability that would allow him to restart and fight normally, basically the second bankai in SS that can repair itself.
So the question would be, why did mayuri say the bankai was weaker than before and kon fixed it to whatever extent he could? Simple, ikkaku is not familiar with the capabilities of his bankai because he generally is too much of a moron to even ask his bankai. Ikkaku did not care about using his bankai, he would actually rather die than having people find out about it. So it makes perfect sense he never actually bothered to master it properly. Any thoughts?
First things first, I think the Non-Repairable Bankai revelation is a recent addition to the lore and Kubo had enough leeway to make cases for Mayuri, Renji, Ikkaku, and Komamura. I don't think it was always like that. Before Mayuri told us about Bankai's not being repairable, I too assumed that Ikkaku's Bankai was a "glass cannon", that was only good for short burst and is easily breakable, though it'd repair itself when Ikkaku rested.
Your theory is great and it would be a great asset if that were the case. Plus it'd actually mean that he grew as a character if he finally swallowed his pride.
However, I personally don't think Ikkaku was worth it. Harsh, I know, but he just wasn't. His whole mindset is an issue. You already said it, Ikkaku doesn't like to use his Bankai and will risk the well being of S.S. by not using it. But it's not just that. Unlike those who were taken to the Royal Realm, Ikkaku has apparently lost his drive to surpass Zaraki and seems content on just fighting under him. He must have some sort of relationship with his Zanpakuto to even achieve Bankai, so I wouldn't think it's just him not speaking to it and finding out other abilities. That could mean that after he achieved it, he lost the drive to further strengthen himself. All of that is probably reflected in his Zanpakuto. It's fragile because, on some level, he doesn't want it to be strong. He's his own worst enemy. Also he isn't a main character or essential secondary.
Ikkaku wasn't in SS at the time the Invasion was going on, i remember him and the 2nd seat was running threw a forest or something (if i get time i'll find a link)
If iba's speed had an effect then ikkaku's mentality should change to strength before pride. I don't think ikkaku lost the drive to strengthen himself though. As far as we know ikkaku does train to become stronger, he simply did not put time into developing his bankai because he did not plan to use it or risk anyone seeing it. I don't think he simply does talk to his zampakuto though. In fact, we have seen him actually commuting with it in the past. It is specifically his bankai that he did not appear to put much time on in the past.
I was just wondering this same question.
I think kubo blew it with Ikkaku. I always thought his bankai should be allowed to explode. It was portrayed plain as day that it breaks easy back when he fought Edorad. Edorad even notes this about it.
Then Kubo goes and uses it as the prime example of what happens when a bankai "breaks". IMO Ikkaku was never ment to have a broken bankai, He just got tacked on the new concept of broken, weakened bankais.
He trains physically sure, but if he still isn't learning more about his Bankai he is essentially rejecting a portion of his power, considering the revelation we've seen about a Zanpakuto's relationship with it's wielder. I think at one point in time he did plan to use it, but he chose not to sometime after he achieved it and stopped learning more about it. He has a good relationship with it, but he still refuses to use it's and his true power.
Do people know of ikkakus bankai? My memory is fuzzy but he did hide it a long time. Could it be that they just didn't know?
1) Ikkaku is stupid and won't use his bankai even when he, his friends and his mission are in danger.
2) The last thing he needs is Royal Guards telling the whole Gotei they're gonna take him along to fix his bankai.
3) Bankai theft problem wasn't solved back then. Ichigo's bankai was unstealable, so it made sense to repair it.
4) His bankai is weak and broke while piercing a Fraccion's Hierro.
In other words, let his bankai dominate fillers and have minimal screentime in canon arcs.
Yumachika, of course
Renji somehow figured it out
Iba also somehow figured it out
Komamura found out through ease dropping
Mayuri and Akon because they tried to fix it
And Ichigo 'cause Mayuri's apparently a gossip and doesn't know it
2) Thinking about it now, it's possible Nimaiya approached him and he said no for that exact reason, in which case your first point is doubly true.
3) They repaired/upgraded Renji's as well so it probably wasn't that.
I actually expect it to make one more appearance, although I expect him to fail and the chapter to end with Yumachika saying "Bankai."
I thin that Ikkaku was not taken to the royal dimension because the royal guards didn't see the same potentials as in rukia, renji, byakuya and ichigo, and because they are ichigo's friend and main lead characters.
I think it's just related to health issues, really. Rukia, Renji and Byakuya were taken to Soul Palace to receive treatment in the first place. Ichigo's case was exceptional. If not for that, Royal Guards should have trained all SS guys in every way they can, but they didn't have such an intention. Had Ikkaku been severely injured, as well, I suppose he'd also receive the same treatment. In that sense, I feel like the asauchi training phase was a bonus for Renji.
Byakuya is the leader of the most influential noble clan and noble families most likely have ties with the Soul King and the Royal Realm, I think it has something to do with the short trip. Renji is Byakuya's vice-captain and Rukia is his sister, so it's not surprising that they accompanied him. I guess neither Kenpachi, a commoner whose condition was stated to be as severe as Byakuya's nor Ikkaku who serves under Kenpachi with a similar mindset are worthy enough to be admitted to the Royal Palace. It seems to me that Nimaiya doesn't particularly care whether Ikkaku's bankai is broken or not, if he keeps track of every asauchi, I guess he also knows who has bankai and in what condition that bankai is. It may not be his concern to help Ikkaku out, it's not as if fixing Ikkaku's bankai will make a big difference in the grand scheme of things anyway. This is IMHO why Ikkaku wasn't taken to the Royal Palace.
the answer to your question is quite simple, even tho Ikkaku has a Bankai he is still a 3rd seat and his Power is on par with a Vice Captain, even if you were to train all the VC and give them Bankai it wouldn't Help or Change the tide of war in any way because the amount of time they have to train them is limited to hours not weeks or months, the SR are basically Captain lvl Shinigamis without Volstandig so you do the math.
I coulda swore the only reason each character who was sent to the Royal Palace were sent is because they deemed the Gotei's healing abilities too weak to get the job done. Ikakku likely wasn't hurt enough that their expertise was needed.