The Freedom Devil (Attack On Titan/Chainsaw Man X-over)

[GM Ambition]

The last thing he remembers was his failure.

Failure of what exactly? He failed to free his people from the cycle of hatred that haunted them for years. When he finally found a way to relieve them from their burden, the very same people he tried to protect turned their backs on him, they betrayed him, and they killed him. Those people were his friends and his comrades, and they fought against his ideals.

Their actions were nonetheless, justified.

Eren Yaeger knew that killing everyone outside Paradis was a downright villainous act. No matter which way one looks at it, he committed genocide. And he paid the price for it, by the hand of the person he had feelings for.

A fitting end for monsters like him who got sent to hell and suffer from the consequences of his actions.

Hell, a place where the primal fears reside. The place where the first concepts of evil were created to haunt the Earth from the very first day. Concepts like slavery, torture, racism, and… war.

All of these concepts manifested in physical form and Eren could see that the religions in his world were no mere exaggerations. Monsters roam around endlessly, mauling other devils until there is no more than a puddle of blood remaining, fighting each other to the death, only for them to revive and repeat the process again.

He could see why Hell earned its name and reputation.

The sky which would normally have a clear blue color was replaced by countless doors. Each of them opened whenever a devil died and needed to be revived. They were the reason why the devils were effectively immortal. And they were destined to suffer for all eternity as soon as they arrived.

Eren knew this and yet he refused to give up. He kept fighting.

He didn't know what he was fighting for. He lost everything, his home, his friends, and his name. He had nothing to lose in hell. There was no reason for him to even try to fight.

Yet he still fought with his all against the terrors of Hell, because he felt that he must. There were monsters that were far stronger than him, The Darkness Devil, Guts Devil, Knife Devil… he could keep going for ages. No matter which titan he threw at those monsters, be it the Warhammer, or even the Founding, those monsters always overpowered him. Still, Hell never let him go, so he always came back and kept fighting. He has never died once since he arrived.

In his penance, he has fought against countless deformities. Monsters with thousands of eyes that were spread from their entire body, a pile of human heads that carried pustules from all over their faces. A sane person wouldn't last a minute in this place.

No matter how horrifying those monsters looked, the devils that resided in Hell were already used to their monstrous appearances, so encountering others of their kind didn't faze them one bit. Eren was no exception to this.

But there was one devil that even most ancient beings of Hell feared. Eren–in his Attack Titan form–heard it approaching.

The sound of chainsaws.

All the devils in the vicinity put aside their differences for a brief moment. Eren, who was currently facing his 500th battle against the Darkness Devil stopped as well to see the source of the sound. The faces that composed almost the entirety of the Darkness Devil's body started to scream in agony.

Eren widened his eyes. Was the mere sound of chainsaws enough to scare even a powerful, primal being like the Darkness Devil?

The monster disappeared from sight, leaving Eren and a couple of devils on their own.

Nuclear Devil, Drug Devil, Stress Devil, and him, the Freedom Devil, remained.

The Attack Titan squinted as it tried to get a better view of the silhouette that was presented in front of them. It was a black armored monstrosity, with spikes adorning all of its body. It had four hands. Its hands had long, highly spinning chainsaws. Its skewed head had a mechanical form that highly resembled to that of a chainsaw, with the spinning blade standing out on its forehead.

The devils wasted no time and lunged toward the Chainsaw Devil. Stress and Drug had no time to activate their abilities as they got pulverized by Chainsaw's rapid assaults. The Nuclear Devil tried to unleash one of its bombs, only to be caught by the jagged fangs of its opponents.

Blood splattered everywhere as the Nuclear Devil got mauled by the Chainsaw Devil. All of it. Eren could the Nuclear Devil's memory slipping away from his mind.

Now he understood why the devils in hell were terrified of Chainsaw. Its power was terrifying. It had the power to erase concepts by eating them! This means that if Chainsaw eats him… then Freedom will be not possible.

But Eren will not be scared by that fact.

He was livid.

No matter how eldritch Hell looked like, no matter the dangers it faces, the Freedom Devil will keep moving forward, until its very existence is erased.

Both devils roared and charged at each other, ready to die.

And what followed, was total darkness.

 

[GM Ambition]

"Lei!"

Lei's eyes shot open as he heard a woman's voice calling for him.

His current name was Lei Jianjun. Despite living in Xinjiang, China, and having a Chinese name, he doesn't bear any attributes resembling his late parents. He had big green eyes and short brown hair in contrast to his parent's black hair and small brown eyes.

An odd phenomenon but not entirely impossible. There are a few cases in which children are born entirely different from their parents due to a weird gene mutation.

The six-year-old boy in question was currently sitting under a tree. He gazed towards the sky, wondering about his odd dreams that always appeared at night.

He always dreamt about that mechanical sound. The sound of chainsaws.

He remained focused on the sound that he didn't notice an old nun approaching him with a disapproving look.

"Lei, can you please stop daydreaming and go buy us some groceries? Your brothers are getting hungry over here. And I will not start cooking food after 3 PM."

Lei opened his eyes and glanced at the nun with an annoyed look. The lady remained stoic and crossed her arms as if daring him to make any objections.

'I better not say anything… I don't want to eat leftovers again.'

"Fine Mei, no need to give the look, I'll go right away."

Mei's expression softened and she let out a soft smile. She took a handful of yuan and tossed it over Lei's face. The boy recoiled from the hit as the stack of papers fell over his face, leaving a big red mark.

"Ow, what was that for, old hag!"

"So you can finally get a move on," Mei said, a vein popping on her forehead. "And feel free to sleep under this tree for the night if you call me old hag again."

"Y-Yeah, sorry about that," Lei said as he quickly stood up and made his way to the front gates.

"Wait, Lei!"

The boy glanced over his shoulders but turned around as soon as he saw the nun running towards him and enveloping him in her arms.

"Be careful child, I know you have a rebellious spirit, but for your own safety, please keep yourself out of trouble. There is only so much I can do to bail you out."

Lei couldn't contain his annoyance and tried to shake himself out of her ironclad grip, to no avail of course. Mother's love is a powerful force. He gave a sigh of resignation and looked up at her.

"Alright, fine, I'll try not to go crazy out there, but can you please let me go?" he said. Mei let him go and waved him goodbye.

"I will be waiting for you, then."

(X)

Lei left the grocery store and walked back toward the orphanage. He took his time to check the contents of the bag for any missing items and smiled as he saw everything in place. He could look forward to eating Mei's exclusive Blackfire Mapo and the dread his going to feel when his taste buds burn into ash.

"Hey, come back here!"

Lei stumbled backward as he felt a hard shove on his back. He almost fell on his back but managed to regain balance. The person who pushed him paid him no heed and kept running forward.

Puzzled, Lei narrowed his eyes to see who pushed him. A little girl, who looked no younger than him. She wore a muddy blouse and ragged jeans, a standard outfit for people who are unable to afford proper clothing.

What caught his attention the most was that the girl had one-half of spiky pink hair.

Yes, you heard that right, half, the other half of her head was gone, leaving the brain for all the world to see. Lei could swear he could a small amount of brain matter hanging around her.

He didn't realize Fiends could be that ugly, but he cannot judge them. Possessing a dead body should have… extreme complications, to say the least.

An armed soldier soon followed suit in the pursuit

"That was my money you damn fiend!"

A sense of dread came to Lei when he saw the soldier catch the girl and pulled her from her hair, dragging her into an alleyway. He understood what happened when the CCP got its hands on delinquents. They are tortured and then thrown into jail for a really long time.

However, a delinquent who is also a Fiend is another story entirely.

It was widely known that people in eastern countries do not appreciate foreigners, but over time, they have learned to tolerate them, as they didn't pose a threat to society. But as the number of Fiends started to rise recently, it appears that it lit a flame within the heart of the Chinese people. They hated them with a burning passion.

A devil being the reincarnation of a former Chinese citizen was fine for the most part. The people learned that they were completely different from their past lives, and as such, they treated them as different people.

But a devil possessing a dead body? A body that is supposed to be considered sacred? That they cannot stand.

Only a select few tolerated the presence of Fiends in China. The military wasn't one of them.

Lei knew the fate that awaited the girl. That was enough reason for him to tail the soldier to the alleyway.

He wasn't surprised by the sight of what the soldier did to the child. The reason why Lei's hands were clenching the wall so hard was that he felt a completely different emotion.

Pure unadulterated rage.

Battered and bruised, the girl began to wheeze as the boot was removed from her mouth. No matter if the child committed petty theft, nobody, absolutely nobody deserved that kind of abuse.

"Think you can steal from me and run away? Think again you half-faced bitch!" the soldier said as he stomped the girl's body, making the girl vomit from the pain.

Lei could barely hear the words coming from her mouth.

"Halloween…"

Those words were enough for him to step in. He ran towards the girl and stepped in between them.

He could now see now that the soldier was twice as wide as he originally expected. He couldn't see him well due to being far away to be out of sight.

That didn't face though, it just meant that he gladly take up the challenge.

"Hey man, you got your money back didn't you?" he said as he raised his hands in a placating manner. "Don't you think you should leave her alone?"

"What was that punk?" the man said as his face twisted in disgust. "You actually defending this freak who stole my money?!"

"If she stole from you, then just arrest her!" Lei said, his face showing no signs of fear. "She doesn't deserve to die for being a child trying to get by."

The girl merely looked up at him. Her heart-shaped eyes started tearing blood, if it was because she was crying, or if she was hurt, Lei didn't care. He only wants to do what he feels is right.

The soldier merely let out a condescending laugh. He began to pull out his baton and made his way toward Lei.

"Sod off kid, you have nothing to do here. Get out of here before things get… ugly."

There was no reason to kill her. No reason at all.

But Lei understood how rotten the military was in this country, how they abused their power for their own gains. They only cared for themselves.

That's all the reason he needed to end him.

'Sorry, Mei.'

Lei quickly grabbed a bottle from his bag and broke it. The sudden action caught the soldier off guard, earning just enough time for him to hold the shards of broken glass and hurl them toward the officer.

"AAAAAAAAAAAGH! YOU LITTLE SHIT!"

The soldier shook the shards of glass off his face and opened his bloodshot eyes.

Lei gritted his teeth, he failed to blind the man and now was in big trouble, but he knew that if he dodged the attack he will be–

'Huh?'

A direct hit. Right into his neck.

Lei's eyes widened as he lost the feeling of every part of his body, he fell felt flat into the ground. He heard something snap.

'I can't move, I can't breathe, why?!'

Was the hit strong enough that it snapped his neck?

'Dammit, I knew this was a terrible idea from the start!'

Going after a trained soldier with no weapons and no training might have been a bad idea, but he wouldn't be able to live with himself if he left the girl to die. Still, his inability to formulate a plan backfired him multiple times.

"This what you get for trying to play hero, trying to save a fiendish piece of shit… you must be out of your mind!" the soldier said as he grabbed a handkerchief from his uniform and cleaned the remaining shards of glass. The soldier pushed his baton towards him and nudged, only to meet a cringing sound of broken bones coming from him.

"Shit must've killed him by accident."

'You think that because the fiends are oppressed by the law, you can do whatever the fuck you want?!' Lei wanted to desperately get his thoughts known, but he was met with the inability to speak. He wanted to move but was met with a brief twitch on his hand. 'I'm not having it, I'm… Not. Having. It!'

He paused his train of thought as he noticed something weird, his hand just twitched. He shouldn't be able to move it at all. He also wasn't losing consciousness despite a snap of the neck being an instant kill to any normal person.

He noticed that steam wanted to come out from his mouth but Lei quickly closed it. The last thing he needed was for the soldier to find out that he could miraculously move again. His efforts prove to be successful when the soldier moved past him.

"Ugh, just what I needed." the soldier sighed. "Better drop him to the sea, no one will find him there. And you…" he glanced towards the terrified Fiend and unlocked his holster. "You've simply seen too much, freak."

"Halloween!"

Lei gritted his teeth and quickly ran towards the soldier who still had yet to grab the gun.

"What the–?!"

The soldier grimaced as he took notice of the boy that was supposed to be dead, but it was too late, he already took hold of the gun.

"A devil? Crap!"

Lei didn't waste any time and took the shot, right into the man's back. The man screamed in pain as he fell on his back. His body started to shake many times before he ceased and started to scream again.

Lei approached the man slowly, gun still at hand, and pointed it right into the man's head.

"MY BACK! I CAN'T FEEL MY LEGS I CAN–" he pleaded as tears came out of his eyes."MERCY, PLEASE!"

Even after all the pain he caused, he still has the gall to plead for mercy? And to think that there are more soldiers that are the same or even more despicable that this piece of trash. That they can abuse their authority to kill anyone that slightly displeases them? And then the only thing the government does is apologize and the next thing you know, these people get to roam freely while the ones they killed do not.

The mere thought of that filled Lei with so much rage that he ended up seeing red.

"Die…" he muttered. Then his eyes lit up and he snarled. "DIE!"

Instead of shooting the man, Lei bashed him in the head with the gun with so much force that it drew blood.

He bashed him again.

And again.

He bashed him repeatedly until he managed to calm himself down after he saw the bloodied mess that was once the head of CCP soldier, now with his skull caved open.

He himself was covered in a bloodied mess, his hands, his face, and his clothes were all covered in red. He turned to check on the girl, who watched him in awe.

He held out his hand.

"You alright?" Lei said as he let out a smile. The Fiend nodded and took his hand, her face still in awe after the earlier display.

The girl ran over to check on the dead soldier. After briefly looking at him, she let out a noticeable scowl and spat on him.

Lei snorted at the sight. That's more or less what trash like him deserves.

"So, your name?" he said. The girl looked at him and let out a grin.

"Halloween!"

Lei blinked. That couldn't be right.

"Your name is Halloween or are you a Halloween Fiend?"

The girl pouted and stuck her tongue out. Lei couldn't deny that the girl had a strange way of saying that she was mad.

"Okay, so it's neither of those things, right?"

The girl nodded.

"So I'll ask again, what's your name?"

"Halloween!"

"You're fucking with me, aren't you?"

The girl furiously shook her head and looked to the side. It appears that she can only say Halloween and that makes things more difficult than they already are for Lei. He just killed a soldier to save a stranger and was pretty sure that the CCP would come for him unless they run away now.

"You know what? I'll ask you more questions later; you can answer them if you want to or not. First, let's get you cleaned up at the orphanage." Lei said as he grabbed the girl's hand and started to run away from the murder scene.

(X)

Lei stopped running and started to pant from exhaustion. When he saw that no one was following him, he let go of the girl's hand. He sighed in relief, finally being able to let go of that entire predicament.

When he turned to see the girl, he could see that she was panting as well. It was probably a bad idea to make her run as far as he did consider their differences in physical prowess, even if both of them were inhuman.

'A devil? Crap!'

He shook his head as he briefly remembered the words of the soldier he killed, but he could see that they hold merit. He got his neck snapped and shrugged it off as if it was Tuesday.

"Hey, you have nowhere to go, right?" he asked the girl who looked at him for a brief moment before she started to twindle her thumbs.

"Halloween…"

Lei sighed, deciphering what this girl had to say was probably harder than killing that soldier.

"Well, you don't have to worry about that anymore," he said as he gave her a reassuring smile. "You can stay at our orphanage as long as you like! Provided of course that you're willing to help inside our house. And you better be prepared, because the lady of the house is going to work us to the bone."

The girl beamed at his words and nodded vigorously.

Lei took a deep breath and relaxed as he saw the orphanage in sight. As he looked at the groceries at hand, he took a note that he should come up with a story as to why he forgot the bottle of olive oil.

He stopped as he felt the space around him shake slightly, then it started to up its intensity, then it shook so hard that it made Lei and the girl fall into the ground.

"An earthquake?! Hang on!"

He ran towards the girl to shield her from any falling debris but stopped as soon as the earthquake came to an abrupt end.

"What… happened?"

He turned around and felt a hole forming in his stomach, he tried to form words but couldn't out of the dread he felt as he saw the total destruction in front of him.

The site where the orphanage stood was suddenly reduced to complete dust. Nothing remained, as if it was wiped out from the map because of God's will. A static sound was heard from the megaphones of the streets.

"Attention, the following cities have been attacked by an unknown force: Tibet, Gansu, Sichuan, Yunnan, Qinghai, and Xinjiang. Estimated time of the attack: 37 seconds. Current death toll: Unknown. Authorities are looking into this issue in detail. Please remain calm and inside of your houses until further notice. The Chinese government appreciates your cooperation."

Lei got into his knees, flabbergasted about what just happened. From one moment to another, his home and his family were erased from the face of the earth.

'Maybe they all ran away before the attack even started, that should be able to tell me–"

He stopped on his thoughts as he had one piece of cloth fluttering up in the air and slowly descending right towards. The piece of black and white cloth belonged to his one and only caretaker in this godforsaken world.

"Fuuuuuuuck!"

He screamed as he punched the ground in rage until blood started to come out of his hands.

"Who did this…?" he muttered under his breath before letting out an ear-busting scream. "What did this?! I'm going to kill it!"

Suddenly, he felt a gentle nudge on his shoulder. He glanced toward the girl who eyed him with a neutral expression.

"Halloween."

"Shut up, I don't want to hear you right now!" Lei screamed as he slapped away the girl's hand. The girl grimaced and grabbed his shoulders again, this time shaking him with much more force.

"Halloween!"

"What?!" Lei snapped as he turned to the girl with a look of fury. Tears were streaming from his eyes. "What the hell does Halloween even mean?!"

The girl merely let out a mischievous smile. Her back straightened and her demeanor changed instantly. Suddenly, Lei found himself not kneeling on the street, but rather, he found himself sitting on a chair.

His tears stopped as he started to look around his surroundings. He was inside a massive library, seemingly containing an endless amount of books. Sitting in front of him was the Halloween girl, looking at him with a dangerous glint in her eyes.

"Where… am I?" Lei muttered, still confused about the whole predicament.

"Greetings, everything will be explained to you in just a moment. Allow me to fetch what I need for a second."

Lei felt a chill down his spine as he noticed that the girl no longer sat in front of him, but behind him without being noticed at all. The girl seemed to be reading thousands of books in a second before letting out a pleased grin.

"Who are you?" he asked as he eyed the girl carefully.

"I am the Cosmos Devil," she responded. Lei got startled as he felt the presence of the girl returns right back to her original seat. "You may refer to me as Cosmo once we get out of here."

"The… Cosmos?"

"Ah, let me rephrase. Cosmos is another word for the universe, and the universe itself holds many things that people don't know. As we know it, people have a fear of the unknown." Cosmo said as she let out a sigh when she saw Lei's confused expression. "Enough about me, let's talk about you, and your true identity."

His true identity? Lei had a faint idea of what that could be, but he wasn't sure where could he start. His weird dreams, his healing factor, his unnatural but well-placed rage he felt towards evil people. However, his pondering was overwhelmed by his current emotions.

"Were you the one that did this to my family?"

Cosmo frowned, which caused Lei to glare at her even harder.

"That would be the Gun Devil. A devil that has lurked in the shadows for many years, feeding itself from the global fear of guns. Right now, it holds an immeasurable amount of power and it kills anything that gets in its way." she explained as she closed her eyes. "It's a shame what happened to your family. You have my sympathies."

The way she worded that… it almost sounded robotic, it made him sick in his stomach. Cosmo didn't seem to care at all about his feelings.

"Thanks, I guess…"

She seemed to take notice of his awkwardness and pressed further.

"I wish I could help you with your grief in a more efficient manner, but it will surely come out as offensive for you. After all, I hold no emotions to question the flow of the universe."

Lei rolled his eyes as if that is going to help him feel any better.

"So… this strange power of yours, does this mean that you could have defended yourself against that soldier?!"

Cosmo shook her head.

"That's not how my power works. I'm pretty sure you're smart enough to figure out what you needed to do in order to access here, right?"

Lei took a moment to ponder her question, and it did make sense. She would have perfectly defended herself from the soldier by trapping him in this dimension. What she could do to someone once they entered here is not something he wants to know, but in order to access her realm she must have fulfilled the condition.

His eyes widened, was it really that simple?

"Halloween?"

Cosmo let out a pleasant smile, one that did not hold any malice.

"Yes, that is correct. In order for my power to work, one must say Halloween after I do, once those conditions have been met…" she said, waiting for Lei to finish the sentence.

"Game over…"

"Yes, game over. I was unable to cast it on the soldier due to him not even acknowledging my pleas. He just wanted to kill me, had you not interfered, I would have died."

What a simple, yet terrifying power, but after knowing how it works, it's easy to circumvent it.

"So… what do you do in this library?"

"I'm glad you asked. Allow me to do a brief explanation to not waste any more time." Cosmo said. "This place is not your common library that holds pieces of biased history. This is every piece of knowledge in the universe, factual, untainted. From the first light of creation all the way to the present. Every data of every single human being resides in here."

She then leaned towards him with the most unsettling stare her heart eyes could muster.

"I will make you understand everything about yourself, Freedom Devil."

Freedom… Devil…?

Lei felt a sharp sting on his head as he began to see visions of a very large creature fighting against a chainsaw-wielding monster. It shouldn't make sense to him, yet...

"It somehow makes sense… right?" Cosmo said as she leaned backward on her seat. "It's not that it somehow makes sense, but rather, it should make sense, because you are, indeed, the Freedom Devil."

Lei shocked his head. The more Cosmo talks, the less he will understand this crazy ordeal.

"So, how does this work? You will make me understand everything?"

"About yourself." Cosmo raised her finger. "If I make you understand absolutely everything, you will only be able to think about one thing. You'll be rendered into a catatonic state, I don't think you would want that."

So that's what she does to her victims. Lei gulped at the thought of falling victim to such a powerful attack. He was lucky that this case was different.

"Why are you doing this to me?" Lei asked, still unsure whether to trust Cosmo or not.

She took a long, deep breath and looked him dead in the eye.

"I'm merely repaying your kindness from back there in the alley."

Lei blinked, that couldn't be right.

"What?"

Cosmo looked to the side as she let out an awkward cough.

"Remember that I told you that I hold no emotion towards the flow of the universe, correct?" she said, struggling to get the words out of her mouth. "When I became a Fiend, that statement still remained true, and yet it didn't… the traits of this former human had fused with me, I have become a walking contradiction, but I can firmly say that it doesn't displease me."

This change of behavior from Cosmo… is suddenly alien to him. Is this Cosmo, the Devil speaking, or the girl whose body got possessed by the devil?

"I have seen that you have become confused," Cosmo said as she rubbed the back of her head. "In short, I think I've become quite fond of you, Eren Yeager."

Lei clutched his head as he felt another headache coming. Images of a young boy, watching his mother get eaten by a monster.

"Eren… Yeager…" Lei said as he let out a few tears at the memory. "Why does that sound so… foreign, yet I still don't find it strange?"

Cosmo appeared beside him and placed a hand on his shoulder.

"You will understand once I make you remember," she said as she held out the book.

Now that Lei could see the book fully, he could see that it was massive, containing large amounts of information. The book was titled "The Freedom Devil".

"I will bring out your fullest potential, and with it, you will be able to take on the Gun Devil, and do so much more," Cosmo said as he leaned the book closer to him.

"Do you accept to throw away the name Lei Jianjun, and rise again as the Freedom Devil, Eren Yeager?"

Lei feels like he shouldn't. He grew up in China, took care of the kid at the orphanage, and grew to care for the caretaker. This was his life! He knew that once he grabbed that book, there will be no turning back.

And yet, at the same time, it wasn't. If he didn't touch the book, he would be running away from who he truly is, and that pissed him off to his very core.

He will never run away. He will fight to the bitter end. Whatever this world throws at him, he will be prepared.

'Fight, fight, fight!'

Steeling himself, his hand reached the book.

What followed were massive amounts of information overloading his brain. A normal human would have gone insane by this amount of information, but he could, and he could make sense of it.

A time that has been long forgotten, a time when the world was ravaged by war. A time controlled by people with greed and desire for absolute power.

Names that he once grew to be their closest friends, are now erased in history.

Creatures known as Titans invaded the earth long before the devils did. And the nine titan shifters who stood above them all.

Marley, Ymir Fritz, The Rumbling.

He was no longer Lei Jianjun. His name was Eren Yeager, and it was time for the Freedom Devil to rise once again.

Once he woke up, he slowly got up from the floor and rubbed his eyes to clear himself of his blurry vision.

He saw a woman with cream hair and an eyepatch, pointing a pistol at him.

"Oh."

The next thing Eren could hear was the sound of a gunshot, and he blacked out.