Hello everyone! This is my first fanfiction I hope you like it! I write for the pleasure of writing, I'm a fan of TAMNI and above all I'm a fan of antiheroes. This story is centered on Accelerator, I designed it thinking about what would happen if it were in a situation that would turn it completely from villain to hero without immediately making it OOC and at the same time "unblock" the full potential of its esper capacity. I wish you a good reading, be free to post reviews.

Disclaimer: the To aru majutsu no index series is owned by Kamachi Kazuma.

Chapter 1: Prologue

The esper, the hero and the god

In the cold lands of Denmark on the completely snowy landscape, three figures stood opposite each other.

On one side, there was a boy aged 16 with sharp black hair and dark blue eyes, who wore a normal winter school uniform.

On the other side, there were two figures; a physically 14-year-old girl with wavy blond hair and green left eye, while her right eye was covered by a bandage, she wore a revealing dress, a long cloak and a witch's hat; the last figure was a boy of about 16, wearing a white and gray suit with a lanky physique, pale skin, white hair and crimson red eyes.

These three figures were none other than Kamijou Touma, the owner of the Imagine Breaker and World War III "hero" who was prepared to face the organization known as the Gremlin that was causing unrest around the world, including events in Hawaii and Baggage City, led by the magic god Othinus or the blond haired girl in front of him.

He was ready to expect everything, or so he believed. He never expected to face the white-haired esper again.

Accelerator, this was his name, was the No. 1 of the seven levels 5 of City Academy, a monster able to control all the vectors with whom he came into contact.

Now that monster had suddenly sided with Othinus for no apparent reason, the danger was great but Kamijo would not pull back and face him again.

"I knew they would have sent you, Kamijou." said Accelerator.

Touma stiffened when the esper began to speak, but he didn't interrupt him, simply continuing to observe and listen carefully.

"Always try to please them by acting like a hero, shaking that right hand and defeating your opponents thinking that it is always the best choice." declared the esper.

At this point, Touma could not help but reply "What are you talking about? I am here of my will. Rather, what the hell are you doing? Othinus has caused problems all over the world just to complete Gungnir, involving innocent and exploiting the same members of Gremlin for herself, and you talk as if she was innocent! Why did you take her side suddenly?!"

Accelerator remained silent for a moment and then answered:

"True, she is no doubt responsible for various tragedies and events that should not have happened ..."

"Then why...?" but Touma could not ask that he was quickly interrupted.

"However, this is not an excuse to make her the scapegoat for all that has happened! Many have been accomplices of what happened and giving her all the blame would be wrong and would not solve the problem!" stated the esper with determination.

Touma stopped, surprised by his words.

He could not be considered in any way a close friend of his, so he could not say he knew him well, nor could he consider himself as someone who understood well the feelings of others, but he could say that there was something wrong here. He had fought Accelerator twice, during the transition project at level 6 and in Russia. They had also fought together against Gremlin on more than one occasion so he could clearly say that he knew enough the esper to say that he acted and talked quite different than before.

Not only did he act differently, but he could also notice a distinct difference in his gaze; usually his eyes and facial expression often emanated threats, hostility, or even murderous intent; this time, on the other hand, he had a calm expression, stoic and devoid of malice if not a little irritated.

Another change he noticed was the lack of the crutch, he did not know what happened to the Accelerator for having to use a crutch but he knew that for some time he had begun to make constant use of it, even the last time he had seen it, but now he is to be able to stand without it. And finally, he had called him "Kamijou", he had never done it before, he usually called him "hero" or "damned hero" if he was in a bad mood. It was not his habit in general to call him or other people by name.

Then his gaze settled on Othinus and a thought came to him.

"Tell me, is she manipulating you?" he asked, pointing to the magic god.

"Birdway explained to me that she can easily deceive others and even manipulate them through magic and that she may have used some spell on you." said Kamijo.

"Big words said by you, aren't you the one who was constantly deceived especially from that girl during the incident in Hawaii?" answered Accelerator. "Besides, I'm not controlled at all, on the contrary Othinus opened my eyes to many things that I stupidly and selfishly chosen to ignore, but now everything has changed, every choice I took was my decision and I did it because I thought it was right."

"You are aware that this way you have antagonized the whole world, the Academy City, the Roman Catholic Church, the Church of England and the Russian Orthodox Church, you have just put yourself against all of them, in this way you will not be able to come back to her! Did not you promise you'd come back and always protect her?" Touma tried in every way to persuade him to return to his side.

"I am not going to break my promise, at the end of all this I will return to Last Order and my family, but now I can no longer give priority only to them. I was given the opportunity to remedy my mistakes, but I can't longer limit myself to this, I must use this power to help all those who need it, maybe it could be just a selfish thought but I will also help Othinus, because she deserves an opportunity to redeem herself, just as it was given to me, I will give her a future where she can still smile and you, Kamijou Touma will not stop me! " he declared the esper with all his determination.

"Human ..." Othinus who had remained silent all the time finally spoke, looking at the strongest esper with a worried expression and at the same time moved.

"I understand, obviously I will not be able to convince you." Touma said in a low voice, even though his opponent immediately sensed what he would say later.

"However, I can't allow either of you to cause problems in the world and hurt others, so Accelerator if that's what you think then ..." he pointed his right hand forward and squeezed it in a fist "I will destroy your damned illusions!".

There was a brief silence between the two, until Accelerator gave a sigh, and with a mocking smile answered "The illusions in which I believed, they have been destroyed long ago."

The boy known as the strongest esper was preparing to fight but a voice stopped him. "Wait!" the voice belonged to the girl behind him.

"No, Othinus." the esper promptly answered "I know you want to help me and in other circumstances I would let you, but now you do not have to do anything. This is my battle." He turned to her with a serious but kind expression, trying to reassure her, "I promised you that I would protect you and that I would always win, so now I ask you to trust me."

The girl was temporarily silent and then nodded with a smile.

Later, he turned his gaze from her to the pointy-haired boy, transforming his calm and stoic expression into his classic sadistic expression with which he was known, beginning to speak again. "Besides, I've been waiting for this for quite some time, you've always been a nuisance and I can't wait to have a rematch with you."

"I'm ready." Touma said.

"Let's begin!" answered Accelerator.

Once the preparations were complete, the two figures rushed against each other in a final showdown.

And so, it was that the clash between the one who welds the power of God and the one who purifies God and kills the demons began in the middle of the Danish lands.

Just before colliding, Accelerator could not help but remember all the events that led him to this fateful battle. Beginning from the events that took place in Sargasso.

"Tch, what a nuisance." said a certain albino boy, with a very irritated expression on his face.

He was in the Tokyo bay and to be precise on a rubber boat in the middle of the sea directed towards the base of Gremlin on Sargasso along with five other people.

That morning, during a walk, he had stumbled upon the hero by chance, while he was with the young leader of the powerful magic cabal Leivinia Birdway arguing about the fact that the anti-Gremlin Alliance was moving against this organization, when it was discovered that they had transported their base in the middle of Tokyo Bay causing a few riots to the capital, the group immediately mobilized. At the Accelerator the fight against that organization did not matter much, however, given that the appearance of such dangerous individuals in the vicinity of his house and especially the peaceful place where a certain girl lived joined the battle.

Gremlin had caused many accidents: some collapsed bridges, some streets and some damaged buildings. There were no casualties for now, but by cutting off the various roadways, communication routes and tampering with the computer routes, countless people had now crowded through the streets of Tokyo with every exit blocked. It did not take a genius to figure out what was going on, Gremlin were using civilians as a human shield to slow down both the Japanese government and the anti-Gremlin alliance.

According to Birdway the purpose was to buy enough time to complete the creation of Gungnir, so they had to try and stop Majin Othinus once and for all. The thought of a magical god had intrigued him, because according to the hero a magical god was the magical counterpart of a level 6 esper, someone stronger than him. The idea of confronting this individual had excited him and he thought it would be a fun day after all, but fate had other plans in store for him, for he found himself dealing with a particular unfortunate thing that he did not expect.

Besides the blond girl in the hero's group there were other people, two of these were the silver-haired nun and a little girl named Lessar whose presence was completely indifferent to him, it was the last person in the group who really bothered him, Misaka Mikoto, the Railgun, the third classified of level 5 and above all the Original of the sisters.

Apparently, her mother lived in Tokyo and since the city was now the center of a possible war scenario she joined the group to save her, but she remained surprised when she saw the Accelerator again. The two levels 5 were still in a bad relationship, each bearing a grudge against each other for what had happened during the Sister experiment, now the two esper were again forced to collaborate as in Hawaii to prevent a catastrophe. He had already clarified his position in not wanting to apologize, while she still looked forward to reproaching her actions as soon as she had the opportunity; the last time after the battle with the armed forces of the Trident he did not have the opportunity to say anything because they parted immediately, but this time she would not let him escape and would certainly have clarified their pending account.

The atmosphere between them was tense even if no one else seemed to notice, but then quieted temporarily when the group separated. The hero, Railgun, and the nun headed for a wizard named Freyja, Lessar and Birdway faced some monsters that had appeared among the buildings and he rushed to face two dragons in the skies of Tokyo. It was a bit annoying, since those two-winged creatures flew at almost supersonic speed but with his ability to control the vector managed to fly and move quickly enough to get them and kill them (reducing them in pieces).

Once the work was done, he reunited with his allies at the beach, each with his own battle ended. Finding himself face to face again with the Railgun and with a strong sense of annoyance that struck him, desiring at this point that the day ended quickly or that this alleged Majin entertained him properly. Eventually the group took a motorboat and headed for the place where a certain god with one eye awaited them.

"So, as long as it takes to get to your destination. I'm starting to get pissed off." said Accelerator harshly.

"We're almost there," answered Leivinia.

"I'm getting bored and those two lizards were barely a pastime for me," said Accelerator as if he would soon kill someone.

"Do not worry soon you'll be able to have fun again, and anyway thanks for taking care of the Niohoggr, now the Alliance's air forces will be able to act without too many problems." reassured the blond girl.

"It seems like nothing can change that mentality about murder." this time Mikoto had been talking as she frowned at the strongest esper.

"Yeah, do you have anything else to say, third rate?" asked the boy in challenge.

"Yes, I actually have a lot of things I have an intention to tell you, but we have to postpone it until after all this is over." Mikoto answered coldly.

"You're welcome." Accelerator said, sending her a strong homicidal glow, to which she stiffened with his great pleasure.

This time, however, their animosity did not go unnoticed by the rest of the group.

"Enough you two, we need all the strength we have at our disposal to stop Gremlin's plans, so we need to all work together or we'll lose!" interrupting the quarrel between the two was Kamijou Touma concerned about the situation created by Othinus and eager to put an end to everything, and to do so it was necessary that the two esper put aside personal grievances.

"He's right." Leivinia intervened "I have no idea what the problem is between you, but now you have to put it aside, the enemy is a terrifying opponent and if we do not work together we will perish."

Reluctantly, the two esper followed their request and stopped talking, focusing solely on the adversary they would soon face.

During the journey they came across a giant made of clay hundreds of meters high that apparently stood guard at their base, fortunately no combat was necessary, as suddenly it began to crumble alone, a sign that something or someone their ally he had destroyed the magic core so that they could arrive undisturbed. Eventually they reached Sargasso and the group immediately noticed a series of destroyed ships.

"It seems that Ollerus has already engaged a battle with Othinus." said Birdway.

"Ollerus?" asked Accelerator.

"He is one of the Alliance's strongest wizards, he had infiltrated the Gremlin under the guise of one of his members, he is the only one besides Fiamma on the right, able to temporarily hold his head with the magic god." the girl explained.

"Let's move and deal with this presumed god." said the white-haired monster.

"Well, as planned once we meet face to face with the enemy, we will wait for him to complete the spear and then we will hit him with Imagine Breaker so Kamijou, get ready." she concluded, pointing to the pointy-haired boy.

"I will do it." the boy answered with determination.

The strongest esper was not at all surprised that "the hero" would have had as usual a major role to stop the group of magicians, but he did not expect that he would be involved too.

"And you ..." the girl said pointing at him against " ... you'll have to throw it towards the spear." there was a brief silence, until everyone panted.

"EEEEEHH !?" they all said in unison except Accelerator, who tried to keep a stoic look.

"What kind of idiotic plan is this?" Mikoto asked incredulously.

"Why should this Kamijo be thrown into the air like a baseball?" Touma whimpered.

"Could you explain the reason for such a strange request?" the Accelerator asked in a neutral tone.

The girl who had an amused expression on her face explained casually addressing Touma "The last time you tried to approach her almost killed you, all because you were too slow to act, so as it may seem ridiculous to throw you at full speed with the power of Accelerator, it's the only way to have a chance of success in this mission and I hope you understand it. "

There was a brief silence until someone spoke.

"You're right, we'll follow your plan." said Kamijou frustrated.

"But-" Mikoto intervened but was immediately interrupted.

"No Misaka, I have to do it for the simple fact that it's something that only I can do." Kamijou stated with determined eyes, clasping his right hand.

The girl who, as usual, was touched by her words nodded, but turned her gaze to that white-haired monster with suspicion, fearing that she might do anything wrong with her idiot. He did not trust him in the least and did not even really understand what he was supposed to be here, in his eyes he was always a sadist who cared nothing and nobody, probably had some shady goal, as shown by his facial expression after all.

Meanwhile, the number one esper had turned his stoic to cheerful expression with a maniacal grin that covered his face "It will be fun to throw you in the air." he stated as he watched Kamijou paling.

"Such misfortune." he said.

Advancing to the base the group saw the figures of two bleeding men in the rubble of ships.

"Ollerus! Fiamma!" shouted Touma.

"Were these powerful magicians our allies appointed by Birdway?" thought Accelerator, if they had been defeated it meant only two things or they were incapable or the enemy was much stronger than expected. His thoughts were interrupted by a strange electric shock that hit his body "What was it ?! I did not turn on my electrode, so what the hell happened ?!"

Suddenly the esper realized that something was wrong, as if time had stopped, he could see the rest of the girls motionless and the hero was the only one who was still moving even though he looked slightly pale as if also he had noticed that something was wrong.

"Hello." said a girl standing on the passenger ship.

She wore a cloak and a witch's hat accompanied by a bandage on her right eye, around it gave off an aura that seemed to distort the space.

It took only a moment to realize that what looked like a simple girl was the magic god they had to face. He had never seen her before, so he was surprised by the fact that Gremlin's powerful leader was actually a girl. Despite the danger that she represented, the esper spoke with confidence to the figure.

"So you are the head of all this, I was expecting something more." he said with a brash smile on his face.

"It seems you do not know your human place, be patient, so now that I have reached my goal I will erase all of you." the girl answered casually.

"Do not tell me ... did you complete Gungnir !?" the hero asked as he seemed to be in a panic.

"No." replied the goddess "Ollerus has prevented it, he completely destroyed my plans, it was a total failure." Then he added with an amused smile "But it was this 100% failure that allowed me to win, what I needed was not the launch itself, but to unify all my possibilities in one direction of success or failure and Ollerus did this for me without realizing it!"

The two continued to listen to her Kamijo in an expression of panic and Accelerator with a neutral expression.

The girl continued to explain "Hawaii, Baggage City, the attack on Academy City to take Fräulein Kreutune, was all a bait to achieve my goal, I distributed false information in the world to deceive my enemies, my subordinates and Ollerus himself. " Suddenly a red substance that looked like blood began to come out of the eye patch, but it began to take shape and soon took on the appearance of a spear. The two boys realized what had just happened, Othinus was creating Gungnir alone from her body now that the circumstances had allowed her.

In short, the two acted according to the plan they had previously established to stop it.

"Accelerator!" heard his name from the hero, level 5 immediately activated his electrode and went into esper mode, approached the other guy grabbing his jacket and throwing it at full force to her "Go hero, destroy that fucking spear!" He exclaimed. For a moment the plan seemed to work, but the moment Kamijou was about to touch the spear with his right hand, a multitude of explosions struck him, creating a cloud of dust.

Accelerator could not see what had happened then moved the dust cloud with his powers "What the fuck-" but his words were interrupted when he saw what had happened before his eyes. On the ground, full of wounds and the missing right arm lay the boy known as Kamijo Touma, as he began to bleed from where the arm once was. Level 5 was shocked, the hero had been easily defeated and that right hand, the hand that had overwhelmed him, the strongest of the Academy City and who had completed a world war between science and magic was now easily rejected and detached from the body of its user.

"Sorry but I will not let you interfere." the god with the eye patch said, level 5 looked at her again and saw that she now had a golden spear with her.

"Ha ha ha ha ! Ha ha ha ha ha ha ha ha ha ha !"

The magic god laughed, arching her back.

At that moment Accelerator felt a disquieting sense of deja vu. That laugh was all too familiar, it was the laugh of a madman in the grip of a delirium of omnipotence, a laugh identical to his old self when he wanted to perform a murder in cold blood. He understood immediately that the laughter was the signal that something really terrible was going to happen ... and he had to do something with the hero or not.

"Now that Imagine Breaker is temporarily separated from your body, it's a good chance to get rid of you all at once before that right arm regrows and the power returns to the owner." Imagine Breaker was part of Kamijo even without the right arm and was a point of reference for the pure world, but that power could still be "fragmented" and subtracted from the body of the owner and was something that few (including Othinus) knew. Otherwise, as Fiamma would have done right to purify his rightful right during the third world war when he absorbed his right hand.

Accelerator's mind worked at full speed to find a solution that did not consist of a simple direct attack, at one point with the tail in the eye noticed something on the ground a few meters from him. It was a severed arm, or to be precise it was the hero's right arm ripped off by those mysterious explosions of before. An idea came to his mind was insane, but he did it regardless of the risks.

"I will not allow this bitch to threaten my house or cause damage to the brat!" the esper thought hysterically.

"Now I will show the world what Othinus really is capable of!" said the magic god with a diabolical smile.

"In fact, looking back at these little fights really annoyed me, I think I'll end the world."

And in an instant with a movement of her spear she destroyed the world.

Shortly thereafter Othinus found herself in a completely black world. Everything had been destroyed and the goddess felt a strong sense of satisfaction with the power obtained; or at least initially ...

The silence began after a few minutes to annoy her and she felt a strange sensation of bewilderment and loneliness, until suddenly she noticed something not very far from her. There was a white-haired boy on the ground that apparently did not move, this fact intrigued Othinus, had destroyed virtually the entire universe but for some reason this boy was still there.

As she approached, she noticed something else and knew immediately what had happened; the human had grabbed the severed arm containing Imagine Breaker, or rather the part of it that was related to the pure world, probably the human had thought of using it against her, destroying Gungnir, yet it was too slow to act and she destroyed the world. However, despite the human known as Kamijou Touma was destroyed along with the rest, the esper known as Accelerator had remained alive just thanks to that right arm he had grasped, even if now he was unconscious.

After a few moments of silence, Othinus sighed and expressed her thoughts aloud.

"And now, what should I do with this unconscious human?"

A/N: I hope you enjoyed the beginning of this story, from here on I will transcribe an alternative version of the Othinus arc, with Accelerator starring instead of Touma. To be noted that from this point onwards the events will be different from those who faced Touma, it would also be interesting to know what kind of inferno will experience Accel-chan and how a character in constant development as he would change in the meantime (just see how much has influenced Touma in the canon, and he is a character who hardly changes mentality). I am aware that the introduction is a bit forced and some Touma fans may not like it, but it is necessary to make sense of the story I am about to write.

Excuse me in advance for the grammar, in the next chapters I will be more careful.

Thus begins the long Accelerator flashback from the end of the world to his battle with rival Kamijo Touma.

This is my first fanfiction and I also write it to inaugurate the new year, so happy 2019 to everyone!

Next chapter: End and rebirth of the world.