Sailor Moon theories ☽

Who is Queen Serenity?

Note: this is not my theory. This is a theory I got from tumblr.
Link to the author's blog: http://silvermoon424.tumblr.com/ go ahead and follow them they have amazing posts :)!
Link to original post: http://silvermoon424.tumblr.com/post/120900867638/sailor-theories-who-is-queen-serenity
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So to the theory: Who is Queen Serenity?
Copy and pasted:
Forget Sailor Cosmos; I've always been far more interested in hearing Queen Serenity's origin story.
Now, we do know quite a bit about Serenity. We know that she was the Queen of the Silver Millennium, the mother of Princess Serenity, and the wielder of the Ginzuishou. From what we've seen, she was a very kind, generous, wise, fair, and benevolent ruler as well as a loving, selfless mother. She sacrificed her life- as well as her chance of being reborn (well, that's the implication I get, anyway)- in order to ensure that her daughter and all of her subjects would be reborn on Earth in the far future and given the chance to lead normal, happy lives.

Despite all this, we know next to nothing about Queen Serenity's past before the birth of her daughter. She has no other known relatives and we have no idea how long she reigned as Queen of the Silver Millennium. The only hint to her past is contained in the Dream (aka SuperS) arc of the manga, more specifically in Act 48:

Now, Queen Nehellenia isn't exactly a reliable narrator, but Serenity doesn't refute her claims. If Nehellenia is to be believed- and the manga doesn't really give us a reason to not believe her regarding this particular tidbit- then Serenity is not a native Lunarian. So, given this precious little information, here is my theory as to where Serenity came from.
Serenity was born into royalty on a peaceful planet far away from our Solar System (but still in the Milky Way). Her family looked after the planet and its inhabitants; I imagine that her family looked after a sort of proto-Ginzuishou (more on that later). Serenity had a happy childhood, but when she was a teenager, war broke out. Her planet was invaded by a warlike alien clan and Serenity's people were forced to defend themselves. Serenity's family fought to protect their people, but after years of war and bloodshed, they were forced to sacrifice their lives by using the proto-Ginzuishou (the proto-Ginzuishou was far weaker than the future Ginzuishou, requiring more life energy to produce results that were weaker than what the future Ginzuishou was capable of producing).
After years of fighting, the war ended, but not without terrible costs. Serenity was the sole surviving member of her family, her populace was reduced to a mere fraction of what it was before the war, and the planet itself was left barren and cold. Devastated by her experiences, Serenity (who was only the equivalent of 18 or so at this time) swore to reproduce the peaceful and happy planet of her childhood, to protect what remained of her people, and to uphold her family's duty of guarding the proto-Ginzuishou.
Serenity and her people wandered the galaxy for years, looking for somewhere to call home but finding nothing. Just as Serenity was about to lose hope, she came across a beautiful blue planet that flourished with life: Earth. However, Earth already had a native population, and Serenity's experiences with the invaders of her home planet made her very adverse to settling somewhere where others already lived. Despite that, Earth had a natural satellite that had no native lifeforms, which the Earthlings called the Moon. Despite its lack of life, the Moon itself had a bounty of energy and held massive potential. It was exactly what Serenity and her people had been searching for.
Serenity and her people began to settle the Moon. At some point, Serenity merged the proto-Ginzuishou (which was the Star Seed of her home planet) with the Star Seed of the Moon, producing the Ginzuishou we know. Using the Ginzuishou, Serenity was easily able to build a new kingdom for her people, who had finally begun to strengthen their numbers after settling on the Moon. Although the Earthlings wanted nothing to do with this new kingdom, the kingdoms of the rest of the Solar System- Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto- were intrigued. They had never seen anyone like Serenity or anything like the Ginzuishou. In a short amount of time, Serenity had produced a kingdom far stronger and more thriving than anything they had ever built.
Still clinging onto the ideals of her parents and never wavering on her own convictions for a second, Serenity swore that her kingdom would be a place of peace and happiness; she welcomed the other kingdoms to join her, although she would never force them to. The other planets (minus Earth) flocked to join her, merging into a super-kingdom, run by Serenity, named the Silver Millennium. And so Serenity was finally able to recreate the home planet she so loved... until Queen Metalia arrived and ruined everything, of course.
I'd like to go more into my theories about the Silver Millennium itself, but I'll save that for a future post. But this is how I personally envision Queen Serenity's past!