Philipe gets magically transported to a reality where things worked out a little to the left. And meets Nas'elle. Who explains a lot. In depth stuff under da cut.
Philipe is a half elf, only growing into his** more elven features in his early teens. He took this terribly, being raised in a kingdom that was incredibly racist to elves (and also having worn an enchanted crown since he was three that whispered about how it was his duty to destroy the elven empire). So, lot of self loathing/self harm occured (namely, he chopped off his ears). His life began turning around when an incredible bodyguard saved it. And through many trials he ended up more self actualised, back on the throne (as king consort) and overall pretty happy.
He kept putting down dysphoria to other things. Like- yeah of course he's really on top of shaving- that evil crown had an ancestor in it- that had a beard!!! he doesn't want to look like that evil guy >:(. Yeah he likes the idea of wearing dresses- but doesn't everyone?! He doesn't need to pretend to be this big powerful King anymore- so of course he wants to explore clothing options now that he actually has a choice in the matter. yada yada yada.
Nas'elle, did not have this same bodyguard, and after a successful coup, only her former court mage's mercy saved her from the gallows. She escaped and hid for a few years in the outskirts, watching from a distance as her kingdom fell into ruin. That space away from people gave her a lot of room to figure some things out, even if she was still in denial to a degree when the elven emperor shows up at her door one day, and spirited her off to live in effectively a guilded cage.
She's pretty happy all things considered, got her ears healed, no one even knows about her past- she's a new person now! Even finds herself entangled with the emperor's daughter and is thrilled about that. Until suddenly her girlfriend brings home alternate versions of themselves- including Philipe- who still looks the part of a king to Nas'elle. and who immediately outs her as having being that genocidal monarch from a hundred or so years ago.
** Philipe after this experience absolutely does transition more consciously (he was kind of already presenting more femininely but didn't view it as a trans thing as much as just fashion preferences, after this he feels more comfortable persuing some permanent physical changes), but pronoun wise i'm still undecided on whether he has a preference, as in the campaign itself he wasn't out yet, and being royalty isn't referred to by pronouns very much anyway (your majesty etc).
Nas'elle strictly uses she/her, she puts as much distance as possible between herself and her as "philipe" and the pronouns v much reflect that.