Curious about something regarding Emet-Selch ***Endwalker spoilers***

[Mirhd]

As I undestood it, Emet did know who we were during Shadowbringers, but he considered us an inferior version of ourselves due to being incomplete. He did ask to acompany us through the msq so he could be able to judge our worth.

This.

That was to judge the worth of mankind as it stood now—he stated as such later when he told us that he still found us wanting (us meaning mankind, not us meaning Azem’s sundered self). Not because he recognized us as a sundered part of Azem. He says at the end that we couldn’t be them.

Emet had (tied with Hythlodaeus; he was just a much better mage than Hyth, period) the strongest aetheric sight of all the ancients (part of the reason Azem and Hyth pushed for him to take the seat of Emet-Selch), and could perceive the unique colour of a persons' soul. Early on in ShB when he's spying on our activities during the quest The Oracle of Light, during his observation he says "then again... with a soul such as that...". Logically, there's only one person he could be speaking about, and given his strength of sight, there's zero way he could be mistaken. He knew we were the sundered Azem and was hopeful we could be convinced to side with the him and the other Ascians and tests us, but we're found wanting, yes. At that point it's more that he's unwilling to accept that we're his old friend. A "Azem could have done it, but since she/he clearly can't, this must not be Azem" sort of thing. Strikes me more as rationalizing his disappointment/grief.

I feel it also bears reminding that Emet had our soul stone prepared at some point before our final battle with him, per Hythlodaeus' shade; that quest is Etched in the Stars where we're picking up the soul stones of the lost Convocation members, the final of which is ours. Hyths' shade tells us straight out that even though the fourteenth seat (Azem) was considered disgraced due to us disagreeing with the whole Zodiark plan and defecting, Emet ("a friend", though again, logically it could be no other) had the stone prepared a long time ago, in secret. No, he couldn't accept that we were Azem before we best him; however it seemed he also really wanted to be wrong and had Hyth's shade leave those stones for us. The shade was more aware than the rest (no different from the real life Hyth, honestly), but still clearly influenced by Emet's hopes.

Also, uh... Emet is just Emet. He is indeed a grump-grump but clearly cares more for his friends/in general than he'd ever admit. Not sure why some people (not quoted here) think there's a weird disconnect between Elpis Emet, ShB Emet, and Endwalker finale Emet. One is just him before his myriad burdens, the other is him after shouldering them and going to extreme lengths to rectify what he saw as a great wrong, with the final being him after he remembered and accepted everything else. In Elpis he was actually horrified to hear that he ends up being the cause of great suffering and (understandably) vehemently denies it and us as a result. I mean... if someone told you that you would go on to cause devastation yet ultimately, despite your adherence to duty, give up your goals ("forsake my brethren", as he put it)... You'd likely react in the same way; you'd refuse to accept any of it.

Eh, this is a bit of a ramble as I've been low on sleep so I'm not sure how well I conveyed my thoughts... hopefully this was clear enough.

[Sakurakouji]

Emet had (tied with Hythlodaeus; he was just a much better mage than Hyth, period) the strongest aetheric sight of all the ancients (part of the reason Azem and Hyth pushed for him to take the seat of Emet-Selch), and could perceive the unique colour of a persons' soul.

Hades wasn't unmatched in terms of soul sight. Hythlodaeus had the superior ability (explicitly stated in Tales from the Shadows), but he felt his friend was better suited for the seat of Emet-Selch because of his far, far superior ability with creation magic (as you mentioned). His take was something to the effect of: there's no point in having this sight if I don't have the power to act on it. Which is why he pushed Hades for it after he had rejected the seat for himself.

But yes, I do agree that Emet-Selch knew the Warrior of Light is Azem. It's just that, much like how he said he didn't consider the fragmented beings to be people, he didn't accept the Warrior of Light as Azem. There are other instances throughout Shadowbringers, like when he's talking about Amaurot to the protagonist, and he remarks, "Not that you would remember." If you choose to inquire about "remember" he just says never mind and moves on.

To me, his lashing out toward the end of Shadowbringers was because seeing the vision of Azem within the Warrior of Light was basically proof that you truly were the inheritor of his best friend's spirit. Except he's now on the opposite side of the fence, too far gone to rekindle anything. He had to fight to the death with his best friend, and it made him angry.

[Mirhd]

...

I read that back when it was released, which is why I said "tied"; both their sight was far superior to any other ancient by leaps and bounds, so Hyth being slightly ahead is ultimately a negligible difference. Emet taking the seat was the wiser choice and Hyth knew it. But yeah, still baffles me that people insist Emet didn't know who we once were (or hates us now. what? he's just a grump)... I mean... the game was pretty clear on that point, and he wouldn't have been nearly so disappointed were the opposite the case.

EDIT: I could have been clearer tbf, but I did mention I was low on sleep, so chalk it up to that.