-deep breath- Now that I'm back how about some good news?
SPOILERS for the new Kazuha Character Quest!
You have been warned! 
Last time I guessed at the Kazuha Character Quest. So was I right? Was I wrong? Let's break it down!
So the overall point of my theory was totally off. In fact I'd say I got it backwards. But some of that was due to the timing. I assumed that the reason why Kazuha's quest was happening now was because we needed both his buddy Heizou and also for Irodori to have happened. Neither was the case and in fact what it played like was that Kazuha's quest should have happened a long time ago. In fact I'd say it probably happened before we even knew Scara went AWOL after getting Ei's Gnosis.
Check out the requirements. You only need to complete the Archon Quest and Ei's first quest. They don't even talk about the repeal of Sakoku in the quest only the Vision Hunt Decree. So this quest should have come out a long time ago but I guess MiHoYo didn't know how to place it. If they had put it out with Kazuha's release like normal Character Quests then it wouldn't make sense since it definitely does happen after the Archon Quest. But right after the Archon Quests we already had Ei and Kokomi's quests. (which could have been Yae's back then) Then in v2.2 it would have been Kokomi's quest along with Labyrinth Warriors. Back then MiHoYo was scrambling to figure out what to do about the altered story so it's likely Kazuha fell through the cracks. We even got a Hu Tao rerun with zero connection to the update at all. My guess is v2.2 was when this quest was supposed to come out. We would have played through this first and then learned that Scara went AWOL. These 2 pieces of information then connect together with both the release of the Opulent Dreams set that released in v2.3 and finally Irodori in v2.6.
Anyway because of that it does still link to Irodori and Kazuha's eventual encounter with Scara and we got more of that story. I think we now know a little more detail as to why Scara "destroyed" the Gokaden.
All the way back during Irodori I theorized that he fell for a girl in the Niwa clan maybe Kazuha's great-grandfather's mother and it was out of love for her that he destroyed the Gokaden. But now it looks like the plan wasn't to destroy but to save the Gokaden. Maybe that Goshintou business was some kind of internal politics staged to undermine the Gokaden and have them be subservient to some other bad actor in the Shogunate. Whatever the reason was Scara had them sent to Snezhnaya and it's only after that that he lost interest. Why?
What if it's because that was Niwa's true intention. She came on to the naive young Scara after finding out his connections to the faraway land of Snezhnaya fully removed from Inazuma's shaky politics and in-fighting. With the Gokaden under fire and forced to make an impossible sword - Ei's Goshintou - Niwa's plan was to have Scara threaten them into fleeing and then arranging for them to flee right to Snezhnaya. With that plan accomplished Niwa dropped pretenses of loving Scara maybe apologizing to him directly and then admitting to him that she had a family.
Scara was bitter but he still loved her so he didn't seek revenge. He was done with his end of it and left the Isshin and Amenoma clans alone until later on when he would meet Yoshinori. By then he had another mission to take his anger out on the "mother" that abandoned him. He assumed the name Kunikuzushi and told Yoshinori to tell that to his grandmother. (Of course the baka probably should have guessed that she's either dead or at least Yoshinori doesn't know who/where she is.)
Anyway the elements in my theory actually work out even up to the ending. It's just that there was no direct mention of Scara since this quest takes place before Irodori.
I guessed that the sword itself has a spirit and an unfulfilled purpose that it now wants Kazuha to resolve. Check.
I guessed that Hajime aka somebody from the Amenoma clan would help Kazuha test his blade. Yuuya and check.
I guessed that Komaji would tell him more information about his family specifically the whole Gokaden thing. Check.
Sword is meant to be a godslayer. Misinformed but check. Also that Crystal Marrow aka the stuff the Tatarigami comes from plays into how it could be a godslayer. Check.
Shinto being the core of the story. Check. But it's interesting. It sounded like Isshin is more Buddhist related (isshin = of one mind) and is pitted against the Shintoism here.
Ok so just like I mentioned last time Shintoism is part shamanism meaning stuff have souls. Swords for example. And because of that the swordsman must understand the will of the sword to bring out both of their true potential. For a very popular example look at Zelda. Master Sword can only be wielded effectively by Link and only Link understands the Master Sword's will. In anime you've got among many Rurouni Kenshin who lost an early duel because the will he was exerting into his sword was weak so his sword was broken by his opponent. Then he takes on the Sakabatou or reverse blade sword (nonsense btw lol) and that sword wins out because it shares his will to never take another life.
But Buddhism is 100% the opposite of that. Think back to Ei. I brought this up many times but Ei lacked the understanding of mono no aware from Buddhism or the transience of all things. If everything is transient then no thing has a soul. This is why in those old kung-fu movies you can see martial arts masters and old teachers defeating their well equipped students with something like a twig they picked up from the ground. The idea is to transcend the material world so as long as you are enlightened anything you use can be as effective as you want it to be.
In this quest the Kagotsurube forces its will onto its wielders fueled by the power of - well Orobashi but specifically his lingering malice - the Tatarigami. Where's Xiao when you need him? 
Anyway this actually goes against the philosophy of the Isshin who require the blade to become an extension of the wielder. That's Buddhism. Again the twig from the ground. In this case that twig is Kazuha's Fillet Blade that he just picked up in Liyue one day.
By the end of it Kagotsurube sacrifices itself by placing its ambitions into Kazuha. (O right. Check.) Yes if that scene confused anybody the old spirit inside of the sword dies to help Kazuha forge the new Kagotsurube. This new sword has its own spirit which Kazuha will now partner with to impart his true Isshin will into it hopefully giving the sword a brighter future.
Speaking of which this can also be seen as Kagotsurube being the Kageuchi and Kazuha reforging it into a true Shinuchi. The Kageuchi was used to kill and is stained in blood. Kazuha has now erased that from his new sword and it should stand for a greater purpose. (staining itself in Scara's blood! lol)
Tips and Tricks from a Super Casual Genshin f2p
Commentaries on Genshin Impact and MiHoYo
PS: Also
Shogunate and Sangonomiya? Yeah they totally 2 countries lol
PS2: Also also
Really Paimon? Where were you for this?
