Hello all! With the new, and final season, of Attack on Titan airing, I felt it was appropriate to finally attack this beast and make a crossover story with, of course, Sailor Moon. I have high hopes for this as I adore both animes. This will take place after Sailor Moon becomes Cosmos and midway through season two of AoT. Of course, I own nothing. Unfortunately.

Also, this will not stick strictly to the script with the AoT show/manga. I will take liberties here and there to adjust the narrative.

Please Read and Review! It is what us nerds feed off of when writing these stories. I hope you enjoy it as we take a trip down this crazy path.

Summary: Once she left, she never looked back at that big blue planet. After her Senshi died giving their life force to her, she did everything in her power to stay away. To hide from the memories and the pain, but after spending what seemed like a lifetime in the Andromeda Galaxy, she finally decided to face her past. What will happen when she discovers that everything has changed?

Find out as the story turns in…..

History's Greatest Warrior

Chapter One: Everything has Changed

How many years had it been? How many centuries?

The Cosmic Warrior had been bouncing around the Andromeda Galaxy for so long, she had almost completely forgotten her own galaxy. Her own solar system. Her own planet.

Oh, how she missed Earth. The flowers, the people, the beauty. Truth was that she had no reason to go back there. It would do nothing but stir up old memories from a time she tried to suppress deep inside her mind. She had no life there anymore. No kingdom. No friends. No family. She was the lone soldier. Her duty now absolute. Her enemy forever in her peripheral vision. Chaos. Where the entity went, she followed. Which is why she had been stuck in Andromeda for so long.

After the last battle with Chaos on Earth, where she gained all the powers of her Senshi, the dark force had no interest in remaining within that galaxy. So, it led her to new territory. Hoping to trip her up. Hoping to finally defeat her and turn her heart black.

She sighed. She wasn't sure now if she even had a heart anymore. All that remained was duty. All that remained was keeping the universe, and the lives within it, safe. The universe and fate couldn't care less whether that meant she was isolated forever. How did she get to this point? From the girl who loved companionship to this ice queen who shunned anyone who even looked her way for too long.

The old girl was gone, and she doubted that she could ever bring her back.

Of course, she wanted to check in on Earth. Help where she could. She was certain it still had its problems. Famine, disease, war, death. But the reality of the situation was those issues were beyond her duty. Humans simply had to work it out for themselves. It took so many years to get that through her thick skull, but now it was second nature.

She stood up from the ground and wiped the blood from her lips. This one had been a hard one, but Chaos once again slunk back into its hole. She gripped the Sword of Sealing in her hand as she contemplated what her next move was. Where would Chaos go? Whose mind would it infect next? She closed her eyes as she focused on the universe. She didn't feel it manifesting anywhere. At least not at a concentrated point. Would it stay in Andromeda? Or move on to another galaxy to wreak havoc?

Her silver eyes glistened as she opened them to see the destruction in front of her. Always ending like this. Same beginning. Same ending, and all the lost lives in between. Was it even worth the battle? No matter what she did, she couldn't save everyone.

When she was younger, she truly believed that love and friendship would always win. She believed that she could save everyone, and for a while she was right, but all good things come to an end. She almost wished she had listened so many years ago when she was told to stab Galaxia. To lock Chaos away forever. She thought about trying that again. Going back in time. Seeing if maybe this time would be different and Sailor Moon could actually do it, but she was no fool. It would end the same. It always will. Her heart was too pure then. Even now, she could not condemn Galaxia to such a fate. Not when she had tried so hard to contain the demon. She deserved freedom from it, and who was she to deny her that?

She had contemplated trapping the entity within herself. Killing herself with the Sword of Sealing and being done with the entire thing. The constant battle. The same movie on repeat, but Chaos was too clever. It knew of her desire to do so, and it did everything in its power to see that that didn't happen.

As the wind whipped through her silver hair, she could only think of her Senshi. Of those she held so dear. She missed them. She missed their laughter, their jokes, their love. Her daughter – barely began living when it all came crashing down. Now they only exist in her memory. Tears flowed freely down her cheeks as the pain cut her heart. It didn't matter how many centuries had passed. It always hurt.

She took a deep breath and tried to rebuild the internal walls that kept her emotions at bay. She would never forget them, but crying won't bring them back. Nothing will.

She turned her thoughts towards the Milky Way Galaxy. Towards her home. Could she really afford a trip back? Would she be able to handle it? Now that Chaos was held off for the time being, she just might have time to see what has changed and what has stayed the same. She smiled thinking of the humans and how much they must have advanced by now. She hoped with all her heart that it was to the point where all the ills of the world were gone, and people finally found peace – without her.

The thought had played through her mind so many times. Whether they could make it without her. They had to. She was no longer just theirs. No longer Queen. No longer the peace bringer, or Humanity's Greatest Warrior. Her life was now forever connected with Chaos.

She knew that eventually she would have to go back, if only to sate her own curiosity, so why not now? She could still keep an eye on the demon – their destinies forever entwined. Maybe it was time to return home. To finally see how much time had passed. Who knows? Maybe the humans made it. Maybe they didn't. She hoped the latter was not the case. She would never forgive herself if they had been wiped from the universe.

She raised her hand in the air. Staff replacing sword as she focused on that big blue planet. As she focused on Crystal Tokyo. Those pesky memories. Light began to engulf her as she disappeared, finally finding the courage to go back to where it all started.

As quickly as the light came, it faded away. She allowed her eyes to adjust to the light of Earth's sun once more. Oh, how she had missed that warmth. As she scanned the area, she realized that she was standing in the middle of a grassy plain. Nothing but fields and trees to be seen for miles on end. Her eyebrows shot up into her hairline. Sure, she tried to pinpoint a location somewhere outside of Tokyo, but this didn't look right at all.

Where were the roads? Cars? Life? It all was in a standstill. As if time had reset. She was sure she was near where Tokyo should be, but she couldn't see the city no matter what direction she looked in.

"What the hell happened here?" She whispered to herself.

As her eyes strained to scan the horizon, they finally settled on what appeared to be a giant wall. Well, it was the only lead she had to go on, so that was the direction she was headed. She started to take a step before she remembered what she looked like, if anyone came across her there was a chance that they would freak out. Clearly too much time has passed. Who would even remember the existence of Sailor Warriors? It was best to play it safe, just in case.

Her body began to glow, and soon she stood there as a reflection of her old self. Golden hair once again, now pulled back into an impossibly long ponytail. Striking deep blue eyes. The silver had faded, along with the eight-point star in the middle of her forehead. In place of her uniform, she now wore a black pair of comfortable, but tight-fitting jeans. A white off the shoulder blouse covered her upper half, while a pair of black knee-high boots covered her feet.

As she walked, she tried desperately to find any sign of the world that once was. Any sign that her life here wasn't in her imagination, but there was nothing. Just more grass and that wall.

Why was that wall even here? What was it keeping out? Or in?

She kept moving forward. The wall coming closer as she sprinted off into a fast run. Desperate to find any sign of life. Was her nightmare real? Were all the humans gone? Her pace picked up as she ran with desperation. Until she finally saw it. What was it? It had the shape of a human, sort of, but it was naked. Standing at about 15 meters or so, it dwarfed her small frame. She hesitated for a second before finally deciding to approach it, whatever it was. As she drew closer, the being's eyes snapped towards her, but it didn't make a move. It had the body of a man, shaggy blonde hair, its eyes were huge, and the grin that adorned its face would give most people nightmares, but the Cosmic Warrior simply stared at it. Studying it as it appeared to study her.

The creature knelt to her. Trying to get on her level as best it could. She just approached it as she stared into its blue eyes. There was a look of sadness and desperation there, but also madness. She got close enough to where she could reach out her hand. She touched its face, scalding hot, but she did not remove her hand. It seemed to hum at the contact but made no move.

"What are you?" She questioned the beast. "What happened to you?"

The beast merely looked behind her before turning back and looking at the wall.

"Will I find answers there?" She asked.

It hummed. Neither to affirm or deny her question. Still, it was the only place to start. Cosmos looked and saw a black horse in the distance, feeding off the plentiful fields.

Well, that's convenient, she thought to herself. She managed to convince the horse to come to her. She tried to remember her times riding Pegasus as she climbed onto its back. Grasping at its mane to balance herself as her legs secured around its sides. She looked back at the tall creature as its eyes fixated on her again. That sad look burning into her mind.

"I will find answers, maybe then I can help you." She said as she rode off to the wall, hoping beyond hope that her questions could be answered.

As she continued her journey towards the wall, she passed several creatures similar to the first she came across. They didn't attack her, but their eyes followed her as she rode on. Her mind started spinning. She couldn't shake the idea that maybe they were once human, but what happened? Was this a similar situation to the Youma she once fought when she was still Sailor Moon? Human turned monster? Was there a way of turning them back?

She finally came to the wall and saw a deep hole in it leading to the other side. As if something colossal had rammed right through it. As she passed through the hole, it was then that she finally saw signs of life that had been here. She could see the houses in the distance as she rode faster towards them, but the closer she got, the more she saw the destruction. She saw the bleached bones. She saw a time that was now frozen in sorrow. None were living, but she was certain that humans were once here. Beyond it, in the distance, she saw what appeared to be another wall – just as imposing as the last. There were some of those creatures wandering around here as well. Sifting through the rubble as if looking for something. Was it them that attacked the humans? So why didn't they attack her?

She scoffed at the idea before thinking to herself, You're not human. Remember that. There was a darkness that clouded her mind at the thought, but still she moved towards the next wall. Her heart breaking at each new site of devastation. Lives completely lost and ruined. Why hadn't she come back sooner? She allowed her own emotions and dark past to prevent her from checking on the one planet that would always have her heart. And now look at what happened. Could she have helped? Could she have prevented it?

Her train of thought was soon interrupted as the ground beneath her shook. She looked up and saw a massive creature running full speed from the wall. It was different than the others. Its skin appeared as hard as stone, and there was a focused, determined look in its eyes. They did not wander aimlessly, lost in a fog like the others. They held intelligence. She quickly hid behind a ruined building. Keeping out of sight and unsure of what to do. She didn't know who friend or foe was anymore. Her best option was to observe at this point.

As the creature grew closer, she could make out the very distinct shape of a man on its back.

"A human." She breathed out quietly. The man didn't seem to be in distress, so she simply let the situation be for the time being. She watched as they disappeared, heading for what appeared to be a wooded area based on the trajectory of their path. They were taking great care to avoid all the other beasts it came across.

"What the hell is going on?" She muttered to no one but herself.

It was then that she heard the distinct sound of screaming coming from the top of the other wall. As she scanned it, she could clearly see more humans. Dressed in some kind of military gear.

"Eren! EREN!" The voices filled her ear. They were so desperate. So full of despair. Once she was sure she was out of sight from the large creature, she made her way towards the voices. As she got closer, she could feel a pair of eyes zero right in on her. Before she could even react, the man had made his way down the wall quicker than anything she could have expected. What was he using to propel himself down so quickly? It looked as if webs were coming out of his sides. He landed right in front of her. Swords drawn and steel grey eyes met hers.

"Who are you? State your business." His smooth voice held no emotion, but there was a fire in his eyes that dared her to make the wrong move. This man was a fighter, and despite his semi-short stature, she would bet he was a damn good one based off the display of his agility she just witnessed.

She held up her hands, trying to think quickly of what to say. So much for just blending in with the population.

"My name is Serenity Moon."

And there is the first chapter! I wonder how this will turn out with Captain Shorty. I hope you enjoyed it! As always, please review, follow, like, all that jazz. I should be getting the next chapter up soon.

-Lizzy