Summary:As Eren struggles with the death of his mother, his father visits him and injects him with a strange substance. Afterwards, Eren remembers nothing. It isn't until basic training does Eren realize the effects, and they could not have been better. But humanity is in need of soldiers like him, and it just might require the sacrifice of his own humanity to save theirs.

Rated 'T' for: Language, violence, and mentions of blood and gore. (Tell me if it should be 'M')

A/N: Like the new format? For those of you who have read my other stories, you know that this is brand new. But for those who are joining me, welcome. I've always thought that Eren needed to be the best at something, despite his Titan form. So I gave him a few more…upgrades that came with the injection his father gave him. While nothing completely serious, it still adds a huge effect to the story.

I have never read the manga… I tried, but I couldn't follow it at some points and I had already watched the anime until episode 25. So yeah, there's that. But don't you worry manga readers; I already accidently spoiled it all for myself, so please don't yell at me if I leave something out that comes out later.

Also, this story is going to be almost entirely the same as the anime (except for parts I forgot and am too lazy to go back and check) in the beginning, but will ultimately branch off as Eren discovers his new powers. Enjoy.

Disclaimer: If I can be a Titan, I own Attack on Titan! *bites finger off* …I don't own Attack on Titan…

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A Beast among Titans

A Shingeki no Kyojin FanFiction…

by BlackStarZX

Prologue

Eren was walking from the fields when he heard the sound of a man approaching from behind. He sounded tired, winded, almost to the point of exhaustion.

In a fit of rage, Eren had sprinted across the fields where they worked before Mikasa could follow him. He didn't want a babysitter all the time; he had to grow up and be a man if he wanted to kill all the Titans!

He was regretting that decision right now. The woods around him were tall and dark, not fit for a child his age to be walking home alone.

The running came to a halt as he approached Eren. Eren was tense; he knew it wasn't that uncommon for bandits to try and steal from him. Of course, he didn't have anything, but that didn't stop them from trying.

Many people resented the children, saying that they didn't work nearly as hard as the adults yet still got pity because they were children. They were right, of course… But the children were innocent, they didn't deserve the famine that many people died from.

Eren turned around, expecting a knife to be held at his throat.

What he entirely did not expect was to see his own father, in the flesh, a frantic look in his eyes.

"Eren…Eren, my…son…" The man nearly collapsed from his run, grabbing onto Eren's shoulders and staring straight into Eren's eyes.

For Eren, however, he just stood there in shock. His father. He hadn't seen him since the Wall…

"D-d-dad…Wha-what are you doing here?!" Eren finally managed to get out.

His father had already recovered, and was looking frantically for something in his jacket. "No time. I'm so sorry son…I have no choice…"

"Dad, you're scaring me!" Eren said, now starting to gain tears in his eyes. All this time, and this is what his father says to him?

"I'm so sorry Eren, I couldn't believe…when I heard the news about your mother, I…" Grisha now had tears in his eyes as he held up the object from his jacket. A syringe, already being filled with a strange, colorless liquid.

"Wait, Dad, where were you this whole time?!" Eren slowly started backing away. This wasn't his father! His father was a calm, collected man who loved him dearly! This man was…insane! That was the best word he had for it.

"You are the key, Eren, you are the key! This liquid, it… Just…" He couldn't explain it. He needed to go, now, before Mikasa or someone else showed up. "Eren, give me your arm!" He shot his hand out and grabbed onto Eren's wrist.

The boy struggled to get away, but it was no use. His dad had an iron grip. "Dad, you're crazy! You're still grieving for Mom! Let me go!" There were tears in his eyes, too. This wasn't how he expected his reunion with his dad to be…

"I'm so sorry Eren, I'm so sorry for everything. I should have been with you after your mother died, I should still be there so you and Mikasa have more than just each other." He had succeeded in pinning Eren's arm to the ground, and was now trying to roll up his sleeve.

"Dad, please, what are you doing?!" Full streams of tears were now running down both of their faces. No father wanted to do this to his own pride and joy; it pained him to see Eren with such sadness and confusion in his eyes.

Eren's arm was now completely uncovered, and Grisha paused a moment injecting him. He had calmed down enough to give Eren a brief overview of what was about to happen. "This key, Eren, this key is all you will have when I'm gone! The injection will make you forget that this all ever happened. Remember this key when you are in moments of immense danger, when all that you hold dear is at risk! Use this power, Eren, to protect the world from the Titans!"

His father plunged the needle into his arm, and almost immediately Eren could feel himself falling unconscious. There was an immense, throbbing pain that wouldn't go away, it was like something was alive in his blood…

The last words he heard from his father were "Go to the basement, Eren. There you will find all the answers, I promise you! Keep your family safe!"

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"Eren! For God's sake, wake up!"

He woke with a start.

Armin was looking over him, a concerned look on his face. "Are you ok? You were withering in your sleep, and you look like you're going to pass back out. Got a fever or something?"

The sun was just peeking over the walls. No one else was up yet, only him and Armin.

He was right. Eren brought a hand to his forehead and he felt the cold sweat mixed in with the intense heat his body was giving off.

"Sorry Armin… Just a bad dream…" He replied.

Armin nodded. He expected as much, ever since the Titan's took over Wall Maria Eren's emotional state had been deteriorating. It wasn't as bad as it used to be, but it was still there.

"Just let me know if you need anything, ok? We're going to get through this together. Just as we planned," Armin said, a small smile on his face.

Eren returned the smile with his own, but it still looked a bit like a grimace.

As Armin walked off towards the mess hall, it gave some time for Eren to think. It had certainly been a strange dream. Lifelike, and he felt as if he had seen it before.

He looked down at the key on his chest, currently hanging from a piece of thread. He had no idea how he got it. All he remembered was walking off from Mikasa and Armin, angry at something, when someone…

It hurt his head thinking about it too much. All he knew was that when Mikasa found him on the road, he had a key around his neck that hadn't been there previously. It annoyed the crap out of him, but he had no idea who gave it to him. But he held onto it…because it had been his Dad's.

It was the key to the basement. This meant something. What, he didn't know yet. The purpose of the key was clear. If he wanted to know why he had it, he had to go to the basement.

And how had he even gotten it in the first place? No one but his Dad would have had this key, and he was pretty sure he would remember a meeting with his own father.

That had been nearly two years ago. And nearly nothing had happened since.

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A/N: Good start? It will get better (and longer) soon. I needed to start somewhere, and jumping right into the story's new changes wasn't the best option. But a quick question…

Why are there TWO archives for AoT? There's the English "Attack on Titan", and the Japanese "Shingeki no Kyojin". Still confused? Go to "Browse", then "Anime", and you'll see a list of all the subjects in the FF archive. There is one for Naruto, Sword Art Online…

One for SnK, and one for Aot.

Can someone tell me if there are just people being stupid, or there's an actual difference? If there's a difference, I need to know! Before I publish the 3rd chapter, please, so I can publish it in the right area.

Hope you stay around. I plan for things to get real interesting soon enough.

Cheers!