*Pahanin

Typed up on mobile, autocorrect gets me every time

The thing is though, is that with the Vex's ability to reshape reality at will within the Vault, they are able to erase Guardians entirely from the timeline so that they never existed at all. This is why noone had any memory of Praedyth. Not the Vanguard who sent him, not the other guardians who had fought beside him for decades or even centuries, not even Pahanin and Kabr who entered the Vault with him in the same fireteam. Its this ability that makes the lore of the Vault of Glass so horrifying. There's no way to know how many more Guardian fireteams entered the Vault before Kabr's team. There's also no way to know how many guardians were even in Kabr's team; at least 3 for certain. But Preadyth's quote: "Pahanin was always talking to himself" makes me wonder. The horrors of the Vault definitely unhinged Pahanin mentally, and he fashioned Super Good Advice to help him cope with what he had witnessed. However, S.G. Advice wasn't made until after Pahanin witnessed those horrors (and likely after he escaped the Vault), so he wasn't talking to it. While its possible that he was already crazy and talking to himself, its also VERY possible that he was talking to another Guardian that was beside him at the time. If so, Praedyth remembers Pahanin's side of the conversation because he escaped the Vault and his existence was not tampered with. However, if there was another Guardian there (or two others; or THREE others), then they were erased, just as Praedyth was. And just as Pahanin and the Vanguard have no memory of Praedyth, no memory remains of that other Guardian(s) or their side of that conversation (No wonder Pahanin went mad).

But you see, the Exo stranger isn't a guardian, so I doubt she would have been working with them side by side, I don't doubt though that she might have helped them in the way she helped us in the story