ETA: 5.0 through 5.3 HUGE spoilers.
Another piece of the Hythlodeus puzzle and more ammo to my headcannon.
When Y'shtola asks us what was going on after the cut scene with hythlodaeus, we tell her words to the affect of 'dont worry about it'.
Im watching savix's vod right now and there's this curious line. And i dont think its a throwaway. Its at 2.37.54 in this vod if you wanna confirm:
https://www.twitch.tv/videos/1187670765
Alphi asks "You said an ancient came to your aid. But how is that possible?"
Keep in mind, they werent involved in the fight. At the end it was me and the exarch. They turn up en masse much later. So they never saw the fight. All that's been mentioned thus far is an ancient, not which ancient.
And then Yshtola says: "A gift from Emet Selch... Foreseeing his own death, he made provisions to bring Elidibus's suffering to an end, lest his friend be left to struggle alone".
She then very suspiciously continues: "Or so i wildly speculate. It is unlikely we will ever know the truth".
Now i mentioned that it was wildly convenient that she just so happened to turn up from 'fetching her bags' (which the game made a point of telling you) precisely as Hythlodaeus had finished his story to you. She then asked us what was going on, which we just happened to decide not to mention. Then she just happens to know that a gift was given by a dead character to sabotage his friend and put him out of his misery. Obviously the gift could be his death, but it also just so happens we have a stone given to us on the fly that none of the convocation BAR Emet knows about and which just so happened to completely transform the outcome of said battle. But why would she assume there was even a provision? Why would she even say that? Did she assume there were provisions put in place for every primal and ascian we already killed? No. Just this one. All others are down to us being the warrior of light and imbued with Hydaelyn's blessing. But not this one for some reason. This one its Emet Selch working from beyond the grave to GIFT his friend defeat (which just so happened to be exactly what happened).
Again, not saying this is the smoking gun or anything. But im just adding it into the pile of evidence marked 'very suspiciously convenient'.