Don't worry, this is the last one I have (so far). For the Sailor Moon fandom at least. I think I'll call it a night here and see how these three stories do for a bit. Enjoy.
The Sailor Starlights will actually be boys who physically transform into girls for this. Harry will run into Seiya while he is incognito (at a bakery or other hangout place), Seiya will be charming and they both insta-crush on each other. Then Seiya will meet Usagi and the others, transferring to Juban High School, where Harry will also have just transferred to (Harry is in the same class as Usagi, Ami, Seiya, Yaten, and Taiki) Harry and Seiya will keep meeting coincidentally. Each event will basically become a sudden date (but neither will really see it this way for a while cuz they're both super oblivious).
Then Harry will find out Seiya is famous and a crazy fan will go after Harry. Seiya will feel guilty and want to make it up to Harry. Something will happen (likely some kind of alien attack for dramatic effect cuz apparently I love drama) and Harry will find out Seiya is Sailor Star Fighter and will be super impressed (not-so-secret-crush intensifies).
Seiya will find out about Harry's magic at the same time - like, Seiya and the others are somehow attacked before they can transform and are unable to move or there's a block or something, Harry is there or happens upon the scene and just sees Seiya and the others being attacked by something and goes into Hero mode. They all try to tell him to run away but he stands his ground, directly between all the downed scouts and the attacker, who charges a huge lethal attack to wipe them all out at once (super saiyan style? where do I get these ideas). Everyone is scared and worried and the bad guys launch the attack and taking out his brand new wand (Magical Japan is waaay more lax about the secrecy thing) and shielding everyone, his knees buckle with the force as he extends the shield to cover all of them and the attack becomes a barage. His shield makes a pocket in the force that was keeping everyone down though and they all quickly transform, having decided that since Harry has magic himself he can be trusted – after Seiya tries to get Harry to lower the shield and save himself and Harry vehemently refuses to leave Seiya (or his precious people) to die. Everyone transforms, battle the bad guy, Harry is exhausted, is very impressed (and blushes at the revealing clothes and sudden boobs his love interest has), and drops to the ground.
Seiya de-transforms and carries Harry bridal style, to the collective cooing/fangirling/teasing of the others. Both blush heavily and then later there is a slightly awkward conversation about everything, a sincere confession, smooches and happily ever after I will be ignoring anything that suggests the Starlights are actually 100% girls (Harry and Seiya will both be cool with either/both/whatever), anything that suggests the Starlights have to go anywhere/leave/whatever, and I may or may not hook the other 2 Starlights up with people…Maybe Taiki with Ami and Yaten with Mina? Yeah.
I think this one is my favorite just because you can tell that I was tired when I wrote it since it's way more lax/generalized than the other three. Which makes it more funny and open for more interpretation. Anyway, that's all I have for Sailor Moon/Harry Potter right now, if any of these pairings interest anyone or inspire anyone to write a story I would really appreciate the heads up because I am literally just putting these out there with the hope that an actual writer will see the pairing and (disregarding my shit writing) become inspired to write even a little one shot that I can obsess over for days before needing more. Thanks for reading!