Hayate is the Master of the Tome of the Night Sky, which is a prestigious title so long as the book is functional and fully-intact, but reality-warping healing magic and root-level access to the Book's code by way of being Al Hazard's heirs makes that more feasible than in canon. But hold that thought, because I've got something similar.
I noted a few posts back that there's nothing stopping Fate from being a genuine Sailor Earth since she's got Earth's sailor crystal and she's female. But there's also nothing stopping Nanoha from being that character if we pull a little switcheroo.
Picture this: Nanoha transforms to fight her first youma and does a custom variation on Usagi's old introduction (after blasting the youma away from Naru or whoever, but still). When she starts to introduce herself though, she has to stop and think up a name for herself. Usagi just kind of jumped straight to Sailor Moon if memory serves, so here's a little hint that something's not right.
Nanoha doesn't need purification attacks for most of the series because she's fighting the generals rather than possession victims. For this reason, nobody ever notices that she doesn't actually have purification attacks, just beamspam and her family sword techniques. When the crew finally get around to looking for the Silver Crystal, Nanoha doesn't have it. Fate does. Because Fate is Princess Serenity and Nanoha is Endymion.
I noted a few posts back that there's nothing stopping Fate from being a genuine Sailor Earth since she's got Earth's sailor crystal and she's female. But there's also nothing stopping Nanoha from being that character if we pull a little switcheroo.
Picture this: Nanoha transforms to fight her first youma and does a custom variation on Usagi's old introduction (after blasting the youma away from Naru or whoever, but still). When she starts to introduce herself though, she has to stop and think up a name for herself. Usagi just kind of jumped straight to Sailor Moon if memory serves, so here's a little hint that something's not right.
Nanoha doesn't need purification attacks for most of the series because she's fighting the generals rather than possession victims. For this reason, nobody ever notices that she doesn't actually have purification attacks, just beamspam and her family sword techniques. When the crew finally get around to looking for the Silver Crystal, Nanoha doesn't have it. Fate does. Because Fate is Princess Serenity and Nanoha is Endymion.
This one has potential for heavy drama particularly because Precia is the only person Fate is more devoted to in canon than Nanoha. By the season one finale, even after everything Precia said, even after all of Nanoha's kindness and the TSAB's leniency, Fate was still willing to side with Precia one last time if Precia had only acknowledged her.
Nanoha is the reincarnation of Endymion? I could get behind that. Although you would have to explain how Fate is the reincarnation of Princess Serenity. She wasn't created anywhere in the Solar System, nor was Alicia born there. I hate to say it, but Fate'll be kind of useless in the long run. Well, maybe not useless, but she definitely won't be in the league of any Senshi.
That's easy. Fate (as in destiny, not the girl) plays a certain role in the events of the series, particularly how all the Senshi conveniently happen to meet again in their present life, how Usagi stumbles into every Dark Kingdom plot in the anime, and how the villains always come and attack Tokyo rather than some other city. I think that's what Queen Serenity tapped into in order to make sure all the Senshi reincarnated within a certain distance of each other. Endymion and Serenity were reincarnated into Usagi and Mamoru because U&M were meant to meet and fall for each other on some level. Fate and Nanoha have the same thing going for them; Nanoha is the most suitable host for Endymion's star seed and Fate is both very well-suited for Serenity's SS and she's predestined to meet Nanoha by way of the jewel seed incident. If that means sending the princess's soul outside of the current universe, well that's okay, it'll be coming right back in a few thousand years and it's not like QS wasn't already folding spacetime into a pretzel with that wish anyways.
The only exception to this is CLAMP's version where "destiny" is more like "the way things are supposed to be", but it's possible to circumvent it if you can put up with the consequences.
It sounds like a contrived excuse so you can have your precious NanoFate.
What about Ach Scheisse? That isn't NanoFate.
Weren't you one of the people who went on a rant when an author suggested writing Yuunoha on SB once?