Through all this chapter, there was a nagging feeling at the back of my head that I couldn't properly express, until I finally got to the end: This feels like a begginer's first writing, in a almost AI like way.
Its not bad by any means, all the beats are there: Unknown danger, unexpected circunstances, make allies, fight between allies, bigger threat comes im, we all come together to fight it.
Yet, it feels a bit hollow.
Kintoki's obviously supossed to be the "Musashi" of this chapter, and while he has his moment at the end of "THIS IS MY ANSWER", I didn't feel like finding this answer was that important during the story. He never doubted himself, even in his particular thoughts, nor he gained any massive powerboosts for it, discuting the GOLDEN BEAR, which we already knew existed, so it didn't feel that cool. Maybe for a japanese audience having one of their most popular heroes using one of their most popular mythical swords is supossed to be epic by itself, but it landed a bit flat for me.
Shuten hints at her relationship with Kintoki, and relationship between onikind and humankind in general (onis not eating humans being brought up a few times), yet again, it goes nowhere, besides a measily alliance of convinience. Shuten goes all "HEY THIS IS MAH TURF" on Ibuki, but again, it landed flat because I don't know how much she cares for Oni in general, besides Ibaraki. Maybe it was the time to have another Oni servant appear?
What the fuck was Tsuna's arc supossed to be? Hes hellbent on fucking everyone up, even his fellow 4HK, but then loses to Kintoki and hes "ok i stop now". AGAIN, theres something there with Ibaraki, Medea even says as much at the end, but its not built in the slightest. Also no exploration of Medea/Tsuna relationship as a master servant whatsover.
Talking about the other 2 4HK, ok DW you are not going to show them, but you are telling me the elite of the badass Genji, broken or not, are not going to rise up even if broken and wounded to defend Kyoto from such a threat? Felt like they could've gotten at least a mention like "Oh look the other 2 are defending the other entrances of the city!".
Ibuki shows up dies and lends sword. Thats it. Sure we got BEAST potential lore thrown in, specially with Orochi, who's always hyped along Tamamo true form, but still.
Limbo was supossed to have this hard-on for Danzo ever since Shimousa and even allowed her to come along, yet he did NOTHING to her at all? I don't think they even had any dialogue with other besides "I will defeat you!" at the final cutscene...
And talking about him, sure he is Chaotic Chaotic, doing things just for his own self depraved fun, but he really came out as a poor man joker. AGAAAAIN, theres hint of more with him trying to go all "look at me senpai" with Abe-no-Seimei, but AGAAAAAAAAIN, its not explored enough.
Which is why I say this feels very begginerish:
Kintoki has doubts, but they are never worked in the dialogue
Shuten has some pride as a king, but we literally get only 1 scene for that
Tsuna and Ibaraki have a thing going but it is never shown (you NEED to read his Bond 10 CE to understand it)
Danzou is teased as important, just serves as exposition machine
Ibuki.
Limbo is a knock-off joker but could've been more.
All the beats for a great story ARE there. But they are not explored at all. Maybe this was by design considering the lenght of LB6, like a "breather-chapter", but even still, it was mid. And there is nothing worse than being mid nowadays, as being hilariously bad can still be made into fun dissing, such as Agartha.
Unironically, 5.5/10
Oh and since I always feel its good to base your critique on with a sugestion, heres how I would've done it.
Kintoki has doubts that he is unworthy of standing with his fellow 4HK because he did not get a servant. Contrast this with how laidback Shuten is with her own position as a King withouth a Kingdom (as oni are lmao random chaos), and have her tease him for it, with her questions being "Armor-Piercing Questions" to him.
He then goes on to face Tsuna and pretty much lose the first round, further emphasizing his self worth, and maybe further questioning his own way of doing things because of how professional Tsuna is. Privatelly, imply that Tsuna is depressed due to how he feels he has to act, hurting his fellow brothers (4HK) and bystanders that have nothing to do with this (the Casters, which is also why he insists on being the front-fighter in his relationship with Medea)*.
Babbage's part stays pretty much the same, but this time his sacrifice and wish resonate way more with Kintoki, and are the begging of his "finding of the answer". Seeing such a noble soul in Babbage and knowing Murasaki could've gotten seriously hurt as his fellow 4HK did, Kintoki finds the strenght to raise again.
Raikou scenes happen, Tsuna drama ensues (see * below), which could've caused NURSERY to go berserk, maybe in response to Raikou going berserk herself, or to protect her somehow . While Tsuna's professional pragmatism would've seen him just killing Nursery, Kintoki, as the future children's hero, is able to stop AND save her, pretty much how it goes in the chapter itself. This serves to make Tsuna start doubting himself, further adding to his implied depression, and
to give some much needed confidance to Kintoki.
However, given how there were a lot of comments (that also went nowhere) about "WOW THIS IS HOW THE FUTURE IS", and given the presence of Nursery there, this could go wrong: Kintoki starts buying on his own legend (maybe by asking the protagonist, since the protag knows no one will remember it), and starts tryharding to be the Children's hero, kinda like putting on a Facade.
They fight Suzuka and Touta, and Kintoki, even while "faking" it, is still able to beat them, which boosts his confidence.
Then, it would all come crashing down against Kagekiyo. I'd have them trying to fight her first, losing badly, and Kintoki seeing a lot of Genji dying. While a bit angsty, it would create a question: How can a "Children's hero" face the realities of War? His built-up child-like persona gets brought down by pure HATE, incarnated in Kagekiyo.
Lost and without a direction, someone gives the idea of the alliance with the Oni, and again Shuten guides him, by showing her pride as Leader of the Oni somehow, which leads Kintoki to ask the "right questions" to Kagekiyo, exactly how it happened in the chapter propper. Here, the moment where Kintoki does not actually die to the Genji-killling poison due to having "purified" Kagekiyo's hate is made even more important because it shows him what he can do, when he is "Himself". He is not Kintoki because he is a Childhero, it is by becoming Kintoki that he becomes a Hero, one for everyone.
However, before that, there is the need to deal with Ibuki. I feel like having her be a final challenge where Kintoki matures his idea of a Hero by stading together with Tsuna would serve to maybe tie in both of their arcs? Tsuna getting inspired by Kintoki and vice-versa, with the latter realizing that a mix of "Child" and "Adult" is what he is all about. Maybe add some scenes with Tsuna protecting Ibaraki or the contrary? There is room for a lot of Oni scenes here, with Ibuki as the catalyst. This also finishes both Tsuna and Kintoki's arc, leaving room to...
Danzou's, Limbo's, and the Protagonist.
I'd have tied Limbo's and Danzou's by making Limbo hate that Danzo is ok with being surpassed by future Fuuma, not caring about being in the shadows, and not having strong emotions about it, in Limbo's perspective. That classic "you are what I wanted to be so I hate you" kinda of a vibe, or maybe "You are all that I hate in humanity, I'd never be like you".
With her being a magic robot, and Douman being a very good magician, I'd have him capture her and "upload" some of the evil gods on her, where Danzou would then struggle with her identity. What is she actually? How human is she? And so on. Lots of space for narrative here. Protag being protag gets mad and tries to save her, maybe protag gets a window to do so by Tsuna and Kintoki working perfectly in synch together. But then a tendril of the tree still grabs onto to Danzou and the protag, and THEN Ibuki's sword comes in and makes the save. Maybe a have a swing of it destroy all the seeds in Kyoto (it is THE "grass-cutter" after all), which depowers it a bit, but still makes a very fine sword GOLDEN BEAR can use.
Then have Danzou who connected with Limbo during the possesion process state the obvious, that he is doing all of this to make Abe-no-Seimei recognize him. That Limbo knows how powerfull Seimei is, and that even before beating him, he wants to be acnowledge as a actual rival. Maybe contrast this an "Aspect" of Douman's legend that was ingrained in his Saint Graph yet was never actually true IRL, and that is this contradiction that has made Limbo insane (IE Servant Douman has the "Rival of Seimei" ingrained, but IRL Douman was never noticied by him as his rival, much less his equal).
Limbo goes all tsundere, final fight ensues.
Dunno if it got better, but I tried to tie things more.
*While this would take some focus away from the main narrative, we could even see some insights of this younger Medea on how she feels working with someone who is the opposite of Jason: No charisma, but very professional. Sure this reminds me of Stay/Night, but I feel there could be something there. Alternativelly, if you want to work out "Ibaraki maybe being the daughter of Tsuna's first love", have him project his desire to protect Ibaraki on Medea. Would also make for some interesing clash with Nursery, who is also a child.
*While this would take some focus away from the main narrative, we could even see some insights of this younger Medea on how she feels working with someone who is the opposite of Jason: No charisma, but very professional. Sure this reminds me of Stay/Night, but I feel there could be something there. Alternativelly, if you want to work out "Ibaraki maybe being the daughter of Tsuna's first love", have him project his desire to protect Ibaraki on Medea. Would also make for some interesing clash with Nursery, who is also a child.