Here's a multicrossover idea i've had for awhile but never got around to writing it as at the time i was more focused on my naruto/SM legacy stories so this one sort of went to the wayside until recently
P.S i'm keeping the manga abiliy the senshi had that is the ability to fly even in space
In many realities the rebirth cycle of Sailor Saturn after the defeat of Pharaoh 90 would be uninterrupted and Hotaru would be reborn how ever in one reality due to the high amount of life/holy magic of the holy grail and the use of Sailor Moon's silver crystal caused the Saturn Star Seed to form a copy and for it to be sent to another timeline/reality where there wasn't a sailor saturn before the power of 2 Saturn's destablized the universe all the while everyone but Sailor Pluto was unaware of what happened and Pluto was wondering if the timeline/reality the new Sailor Saturn would born into would be within her ability to view.
In another timeline/reality as James and Lily Potter smiled in their sleep hoping for a child the Saturn Star Seed appeared and merged with the recently conceived child within Lily and the child up until the halloween that to save herself the symbol of Saturn appeared as she instinctively made a Silence Wall to protect herself this would also by pure chance prevent her from getting a soul shard attached to her as it would be destroyed trying to get through the Silence Wall, and when scanned by Dumbledore he would detect the traces of the vile magic cast by Voldemort and jump to the conclusion that young Iris Andromeda Potter now held a peice of Voldemort's soul when it was the opposite and the soul shard was already destroyed and all he was picking up was lingering but fading traces of the magic used.
17 year old Iris stood on the battlements of Hogwarts staring out at the dust remnants of the army of female like creatures blow across the grounds, they had just days before the battle of Hogwarts learned that Voldemort had summoned the creatures using remnants of notes that from what they had found after raiding the summoning location had connections to a memeber of the nobility of Atlantis though though what surviving records show that Atlantis was destoryed before the summoning could take place by fire that rained down from the heavens.
"Iris we're getting reports of these creatures attacking both muggle and magicl London" Hermione says as she came running up to Iris looking worried at Iris and Iris knew why to.
"Then Voldemort's finally done it...he's broken the Statue of Secrecy meaning I won't get into trouble now" Iris says before a orb of purple light surrounded Iris before vanishing into purple motes of light leaving Iris in a japanese sailor fuku type clothes with a glaive in her hand.
"Iris are you sure?' Hermione asks Iris knowing that her first friend still had trouble controling her powers when transformed.
"Yes I am Hermione you know how effective my attacks in this form are against these creatures" Iris says before adding with a smile "Besides I'm not going to leave the non-magicals to be killed by these things if i can do anything about it" as she started to float off of the battlements.
People all over the United Knigdom and the world watched as what could only be demons assaulted London and the weapons of the Royal Military was barely doing anything to them unless it was through shere overwhelming and consentrated firing with the machine guns and higher calibur rifles or in areas where they could afford to use them tanks which was only along the outskirts of London and it was starting to look hopeless when a bolt of purple lightning slamed down in the middle of a group of the demons that the Japanese was calling Youma after the demons of the Sailor Moon series and what was seen standing where the puple lightning had hit caused many to do a double take for standing where the bolt had hit was as the dust cleared the iconic sailor fuku of a Sailor Moon senshi.
"Silence Glaive Surprise" was herd as what the viewers could only call a real life sailor senshi.
The military started pushing forward with Iris who told the military commander who she was helping to call her Saturn which eventually made it's way to the news crews covering the attack which got the Japanese cheering the younger generations more so at a magical girl being real and young girls gained a new idol to look up to but the battle for London wouldn't end until 4 days after Iris had joined in as she knew her most powerful attack would've killed her as she was not yet powerful enough to withstand the backlash that would've happened and she didn't feel like testing if her odd feeling she would just be reborn.
A month after the battle of London as it came to be called the magical enclaves around the world were forced out of hiding some nations like the USA, Japan and various South Americian and African nations it came easy for the USA due to their already semi-intergrated status, Japan because of their culture it actually saw an increase in Shrine goers knowing that magic was real and thus so to must be the gods and for the South American and African nations shamans and witch doctors were still common enough and were basically public secrets as for other nations well the UK by the time of Voldemorts downfall was set up more like Nazi Germany with concentration camps though the magical enclave of the United Kingdom didn't last long with Iris/Saturn's help China how ever eruppted into civil war due tot he fact that Magical China never desposed of the Emporer's family it should be noted that with news of there still being a Emporer of china among the magicals many rual towns and villages joined the magicals thanks to the older generations remembering the time before the communists took over.
I'm going to end this chapter here hoped you enjoyed reading this :)