Author's note: This is actually set in episode 18 of To Aru Majutsu no Index where Accelerator first met Last Order.

Accelerator had realised that he ran out of beverages after dinner and decided to buy some from the convenience store nearby his apartment. Soon, he was done with his purchases and stepped out from the store only for a fool who was sneaking up behind him.

He charged towards Accelerator with a loud battle cry, swinging a baseball bat towards him but it seemed as though the bat had hit an invisible wall surrounding him, and the bat violently flung back in the opposite direction. The impact from the sudden change in direction caused the fool to lose his balance and he tumbled straight onto the ground.

As if on cue, several more fools appeared in front of him. All of them had a smirk on their faces, but that soon turned into agony as they charged towards him with fists raised, only for it to hit an invisible wall and forcefully bent in awkward positions.

Ever since that unknown Level 0 had defeated Accelerator, nobody seemed to fear him anymore. Everyday, people would launch similar assaults on him, but that only ended up in them getting hurt from his passive ability that could reflect any form of vectors. Turning back for a moment to see those fools kneeling on the ground as they squirmed in pain, Accelerator sighed and decided to walk away.

"Despite the fact that I'm still a Level 5, that my powers haven't changed, those idiots still never learn."

Something felt different ever since he lost to that blue, spiky haired guy.

But what could it be?

Accelerator narrowed his eyes as he pondered deeply, but to no avail, causing him to shut his eyes momentarily in annoyance. Walking past a building, he could hear a couple arguing about whose turn was it to wash the dishes now. After that, a telephone conservation about whether Naruto or Bleach was better.

"Let's eliminate the useless chattering."

Setting his ability to also reflect sound vectors, slience permeated his surroundings. Finally, nothing would interrupt his train of thoughts. To some people, it might be terrifying not being able to hear any incoming dangers but to Accelerator who could reflect anything with his ability, it was paradise.

Other than that Level 0, only one other person had succeeded in bypassing his ability. His only friend, the then-strongest Level 5 before him.

7 years ago at the age of 8, Accelerator was transferred once again to another Child Error facility for accidentally hurting somebody with his powers. He didn't mean to reflect a stray soccer ball that went flying onto his path back into a teacher who happened to pass by.

This time, he was the only student in the class at that Child Error facility. One bright sunny morning, he saw another student seated in the classroom. Impossible. Accelerator stared at the girl with shock written all over his face. Could this be the facility's death sentence for the poor girl who had her brown hair tied into a ponytail. Fortunately for her, she was seated in the front row while he was seated at the back.

Not once did he expect the girl to approach him. Anyone foolish enough to do so would certainly end up hurt, or even dead. A group of boys had approached him once in the first Child Error facility that he was in. During a game of soccer, he got so excited that he smashed the face of an unfortunate boy who happened to be in the path of the ball that he kicked. Ever since then, nobody dared to even appear within his range of vision; not even multiple transfers to other Child Error facilities seemed to changed this fact.

"I'm Tsuki, says Tsuki as she introduces herself with great enthusiasm!"

Accelerator looked up at the smiling girl who stood in front of his desk. Another ignorant fool who seeks a path to hell. However, her voice felt very mechanical; similar to how a robot would speak.

"You talk weird, you know."

"Tsuki is born mute, and so Tsuki has a special device that allows me to speak, says Tsuki as she explains."

He cocked his head to one side, "You should just fuck off from my sight."

"Do tell Tsuki your name, pleads Tsuki as she is curious to know."

In his attempt to chase that annoying girl away, he took an eraser from his pencilbox and hurled it at the girl, hoping that this would scare her enough. Unfortunately, moments after hurling the eraser, he realised that it was flying towards the girl at about 120km/h. Once again, somebody who dare approached him would end up dead.

But the eraser only bounced off harmlessly from the girl's face. Accelerator could not beileve what he had just witnessed, this was an eraser flying at about 120km/h.

"Tsuki is the strongest ESPer, a mere eraser wouldn't inflict any harm to me, says Tsuki as she believes that she should be explaining"

Accelerator could only look at her with his eyes wide open. He was the 3rd strongest ESPer despite being a Level 4 at the time, only a rank below Shokuhou Misaki, who was the first to reach Level 5. Surviving an eraser travelling at 120km/h is enough proof of claiming to be the strongest of them all.

"What exactly is your ability...? Did the researchers finally had enough and sent you, the strongest ESPer to kill me?"

"Tsuki... Tsuki's ability is known as Imaginary Vector Creation. Tsuki can mimic certain aspects of your ability through resultant forces."

Any physics textbook would tell you that objects usually have more than one force acting on them at any time. By creating imaginary vectors that would act on the designated object, the overall effect on the object can be manipulated easily. Thus, it is possible to mimic Accelerator's Vector Change ability.

"If you want to kill me now, hurry up and get it over with."

So many people had died from his Vector Change ability. The only reason why he still lived is because nobody was powerful enough to mete out judgement upon him. Today, this Tsuki would be the one to end his life.

"Tsuki only just wanted to be your friend. Tsuki knows how lonely you were, says Tsuki as she understands how you felt all these while."

"... My name is Accelerator."

And this was the start of a new friendship. For once, he finally felt like a normal 8 year old boy who had a friend that he could rely on. After classes, they would always sit under a tree on the field just outside the facility and read books together. Not once did Accelerator found this boring although he liked sports more than reading books; he would do anything for this friend, even if it means doing something that he hated.

One year passed, and the both of them were sitting in the tree as usual, this time chatting about a certain Misaka Mikoto, who was the 3rd person who achieved Level 5.

"Hard work does get you somewhere after all, Tsuki muses as she is impressed that she finally reached Level 5."

Accelerator puffed out his chest and gave it a good pat, "I'll be the next Level 5 someday, just you wait!"

"Tsuki... have something to tell you."

"Yes?"

"Tsuki is suffering from blood cancer and so Tsuki will be leaving tomorrow, says Tsuki as she tries to hold back her tears."

Even though her voice was flat as usual, but yet there were tears streaming down from her face...

"I.."

"Tsuki wants to... hug you before Tsuki leaves."

Accelerator knew that it was impossible for anyone to even touch him; only he could touch somebody, not the other way around. Besides, a single touch from him could spell a certain death to that unfortunate chap. In the end, he was a Level 4 with the control of a Level 1 and hugging Tsuki could potentially kill her despite her ability.

But yet, she pulled him close and wrapped her arms tightly around him.

"Thank you for being... my friend for the past 1 year, says Tsuki with overflowing gratitude from her heart."

Accelerator hugged her back, "Thank you for being my friend too."

A few years later during his involvement in the Dark May Project, he realised that he was now ranked as the strongest ESPer according to the Bank. Perhaps Tsuki had already died from cancer. Still, that hidden #6 Level 5 ESPer in the Bank offered him just a slight but almost impossible hope that Tsuki might just be alive.

Sensing a presence, Accelerator turned his head behind and saw a small, mysterious hooded figure stalking him. Upon closer inspection, he realised that the figure was calling out for him.

"What the hell is that hooded runt saying. Ah well." Accelerator said before setting his ability to stop reflecting sound vectors.

"Wow, how should I put it. To think that you actually have no reaction or whatsoever, that's actually a really good feeling. But, assuming that you were ignoring me, your walking pace seems too natural to suggest so... You must be the ultimate natural person, says Misaka as Misaka tilts her head."

"Pathetic..."

Misaka hastened her pace to keep up with Accelerator who continued walking, "Misaka has been appealing to you her presence continuously for quite some time now! Yet you totally disregarded it?"

He stopped walking and Misaka quickly hopped over to face him.

"Misaka, eh?"

"Woohoo, so you finally acknowledged Misaka's presence, says Misaka as Misaka self-praises herself."

That small, hooded figure was to be known as Last Order, an important person that would change his life forever.