so the problems with changing first perspectives is that it can get confusing who talks. Instead of leaving it to the reader to figure it out based on context, I would announce the character of interest in each perspective change. personally, i would honestly prefer changing to 3rd person altogether

Argo calls herself onee-san in regards to kirito and asuna (who is a year older than kirito), so its generally assumed argo is older than kirito at least.

Hell yeah, this is great!

The biggest problem I tend to have with F/SN grail war fics is that often enough, the lineup of masters has too many connections to truly fight each other. This was not the case here, we have a decent roster of Masters and Servants who each have motivations, and reason to fight each other, and only few cases of holding back. And when that does happen, it stems naturally from the characters, such as Archer's reluctance to kill children.
Even the interactions between the protagonist factions, which are to be expected to turn more friendly in time, are well built up in a way that leads to enough conflict without it seeming forced.

The balance of power works out. Kirito tends to be OP, but here he's on a playing field with others who are similarily powerful. His bag of tricks is deep, but we were warned about it, and it doesn't ex-machina him every time. Of course, older Shirou Emiya being around also helps to alleviate any accusations of OP-ness.

I also really like how you drew out the full realization of Shirou's capabilities. Kirito already knew they underestimated him, but that last action is going to open up a whole new level of WTF.

If there is one thing to criticise, it's how the enemy servants seem to line up for their fights. Whenever one is about to be defeated, another one shows up to position themself as the next threat. It simply seems a bit too neat for me that there were apparently no battles that we didn't see.

Wow that was an awesome read. I can't wait to see Rider vs everyone else!

I was wondering where this story was! Please keep continuing your work!

Fuck you Rider. You can steel all the fame in the world, but of all the people with the title of king of kings you deserve to call yourself that least.
Sorry about that. As for the story I've really enjoyed it. It's for the best that Assassin bought it though. Honestly I thought it was assassin that was going to attack them, so that was a surprise.
I also thought that Rin was being silly preparing healing against a sure kill. She knows Shirou better then me I guess.

hmm unless they can hack a secure database I think you have a plothole since there are multiple minor plot points that rely on Kirito not being known to the public. Rumors about a black swordsman make sense, but the government cracked down to keep the identities of SAO safe.

Ah dungeon diving. RPG hell. Must feel like home to our SAO cast.
Huh Sakura wasn't even mad. Awfully nice of her. so she died from mana exhaustion like her uncle?

Ah Sakura why'd you have to do that.
Still this is good news. She's merely gone full Makiri instead of going full dark Sakura. Compared to skipping all the steps this is only a mild hell no so far.
Unlimited blade works is truly Sakura's worst timeline.

This might just be Shirou not knowing better but Atlanta is a bear girl not a cat girl. They look similar, but are different.
I found Kirito using his super human reflexes to keep Argo from head desking into her food hilarious.
Oh right I forgot about Argo's counter measures. I thought he couldn't understand them because they were digital.

bwahahahaha
A shameful display. Argo clearly is not a fsn character. I mean even Tohsaka is good at cooking even though she was trained by a man who views cooking as a form of torture.
The sheer contrast to their days was amusing.

Oh Argo you crazy magnificent person you.
Well it's not as if the class system is there without a reason. Summoning a heroic spirit in it's entirety is like summoning a god. That would normally blow a fuse in the grail system. Luckily I suspect that Kirito is on the lower level side of HS, so he will be in the 'normal' range for high level servants and 'merely' wreck armies one handed. Instead of you know wiping out the world with one swing like a unchained Gil or Saber would.
I would argue about the relationship between Rin and Shirou except reading the section below it's clear you meant not making a shipping fic out of it instead of canceling their relationship so I approve.
It's a good thing for Argo that her seal of approval is technically correct in that Asuna will be saved, because the grail is probably still cursed...

So Ozzy and Fake assassin.

I’m glad that Shirou got the final kill. Although I didn’t understand why he didn’t use it earlier.
Anyway, this was a great chapter and I’m glad o see that you’re back! Please keep up the great work!

Thanks for the updates! Been waiting for a long time now…

Wonder what'd happen next…