Xaden and Sgaeyl

So, l've read the books in span of few days and can not wait for January! Since reading both books I've been reading posts in fourthwing sub nonstop and I do not think l've seen much discussion about this (or at least particular part of this- Sgaeyl part). There might be spoilers below, even though I tried to avoid specific stuff, so if you haven’t read both books please stop reading now!

First I'd like to say that I'm almost 100% sure there is some prophecy involved in the books that we do not yet know about (and most of young generations don't because Archives hide books and history facts from us), but I am still not sure does it involve just Violet or Xaden too.

Why do I have this itching in my brain for a few days now? Because it seems really strange that Sgaeyl bonded with Xaden. Even Violet thinks so at the end/second part of IF. She says something along the lines how come Empyrean let this happen. I also believe they let it happen because they know about the prophecy and want it fulfilled! Do we have more information about their bond that I missed? Why are they allowed to bond?

What adds to my theory is that they are obviously very important in their history later on, and that can be seen from "found letters" above chapters and Jesinia’s writings. That makes me believe they are more than just war heroes. They (or just one of them) might be Messiahs, demi gods, demi dragons or even spices not yet introduced in the books. I know most people expect her to unite the continent and become a queen (hint: coronet) but I do believe it's more than just that.

Also, if this is true and there is prophecy, I believe her mother knew about it (at least to some extent). And I somehow feel weird about the whole story about her asking him to return the favour and take care of Violet once she enters RQ and keep her alive. This doesn't sit right with me because Xaden's explanation and what he traded with her for kids to enter RQ makes more sense and is honestly IMO the end of the transaction. Why would Gen Sorrengail get add on to this deal? Maybe Xaden knows about the prophecy too and that's additional reason for keeping Violet alive at all costs even before he fell deeply in love, because remember, it was just an attraction at the start. Him not wanting to be fully honest with her also fits this, and him only committing to answering questions. She would never ask him “is there prophecy involving me?”.