Requested by XxAnimuTrashxX , so I didn't know if you meant strong in the physical way or the psychic way. So I just made reader chan both. It's a female reader by the way.
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Mob's chest was heaving heavily as he tried to bring Oxygen into his pain filled lungs. He just started another run with the body building club, and due to his poor physical state he failed on the first five minutes. His body was in pain, nothing but pain. Who knew being physical could be so painful, but...he had to push himself. It was his dream...to get muscles. If he had to push himself to his limits then he was going to, and he wasn't going to rely on his esper powers now.

The club was already far ahead of him, so he felt the need to push become stronger. He wiped his face slightly, and slowly got off the ground. His vision was beginning to darken for some reason, probably because of overdoing it. But he didn't care, he just kept on running. As he kept his slow pace his eye caught onto something in his peripheral vision. A sudden rush of wind came passed him and he finally saw it. A girl, probably his age, with a stunning figure and flowing (h/c) hair. Mob's conscious halted as he focused on the figure in front of him.

Her hair was tied up in a tight ponytail, so it unveiled her neck. Her skin with slight perspiration made it shine in the light. Mob was in complete awe as he stared, even though he kind of looked like a slight pervert. He admired your looks as he could slightly see an outline of muscles on her arms and legs.

The figure was you of course, and Mob felt his mouth open slightly. You caught sight of Mob staring and showed a grin.

"I know it's not everyday you see a girl jogging in her free time, but it's not polite to stare." You said snapping Mob out of his daze. He shook his head and you could barely see the pink on his cheeks from embarrassment.

"I'm sorry." Was all he said, you noted he sounded stoic, and it made you curious. You waved a hand dismissively at him.

"Nah, it's alright. As long as you don't advance on me then we don't have a problem." You said and winked at him. His cheeks turned pink slightly again, but you didn't notice.

"What's your name?" You asked as you stretched. The shirt you wore was loose and lifted slightly showing more of a toned torso. Mob stared utterly impressed at how toned it was, even though it was a slight peek, and he gulped trying to take care of his dry throat.

"Kageyama Shigeno. But you can call me Mob if you want." He said blankly, there was a tiny hint of shyness in his tone.

You giggled poking his forehead, "You're cute." You said bluntly. If Mob didn't have such control under his emotions he would be a mess. Something about you as well just seemed so cute to him.

"I'm (L/n) (Y/n). Nice to meet you Mob." You said bowing, he bowed back.

You raised an eyebrow at him, "Are you on a run too?" You asked gazing at his appearance.

"Uh, yes. I'm in this club because I wanted to build muscles." He said.

You hummed gazing at him a bit more, Mob could feel his heart skip a beat at how intense you were in your observing. Then your eyes glinted.

"Hm, you do seem physically weak." You said making Mob sag his shoulders.

"But you could get there. With some help of course." You winked at him again and Mob felt his heart skip another beat.

A sudden ding from your cellphone caught both of your attention. You looked at the screen looking a little disappointed.

"Oh, looks like it's time to go now. Mob-kun, do you have a cellphone? Actually wait..." You said as you went into the tiny bag around your shoulder and pulled out a paper.

"Here my number. Give me a call sometime and progress on your muscle training." You said punching his shoulder playfully. Mob knew you were being playful but he liked the tone of your voice.

You waved at him, "Bye! I'll talk to you later hopefully!" You exclaimed before running in the opposite direction. Mob waved back as his daze came back. Even though you two just met, he enjoyed how playful and fun you were in conversation. He stared down at the tiny paper littered with numbers, he smiled slightly. It looked like he found another activity to do after school.
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"Mob, you have been typing at your phone for quite a while now. Don't forget about that job." Reigen said as both he and Mob entered an abandoned building. There was word of some sort of psychic fiasco going on, it was difficult for Reigen to deal with so he just called in Mob.

"Huh? Oh sorry." Mob said simply, but his eyes still gazed at the text conversation he had with you. His heart pounded slightly, he liked to have conversation with you. It has been a week so far, and it was the most fun he had in years. You two even had some of the same interests, so it was like he formed an invisible bond with you. He felt like he didn't want to lose that bond, so he kept checking 24/7, while also trying to keep in mind your busy time as well.

"Ok, go on Mob." Reigen said as they walked into the abandoned building. Mob nodded at his "master" and his body glowed a faint blue, there was psychic energy here he could feel it. Although there was another psychic presence and he could feel it. It felt powerful enough as his own, but he knew he was stronger. It got him curious as he treaded into the darker depths of the building.

A huge boom startled him, but he knew that was where he needed to go so he wasted no time running. The scene that he saw made him freeze in his spot.

It was you. And you were in bad shape, your clothes were torn slightly, your arm was cut and bleeding badly, and you just looked flat out tired. He wanted to help but he was frozen, the energy you were emitting was just powerful, even he got chills.

You grit your teeth, and gave out a really strong aura. Your psychic power, it was almost as if you were taking in the energy around the area. You stood on your feet grinning at the hostile entity in front of you. A faint glow appeared around you and Mob watched in awe.

"How are you not down yet?" The entity said with a growl. You just grinned more and chuckled menacingly, Mob almost got shivers. The entity growled sending a telepathic blast, your arm went up weakly and it flowed brightly. A flow of energy that Mob didn't know was there manifested creating a barrier, it was a weak barrier but it still blocked the hit.

"Heh...I...won't go...down that easy." You said in between panting. You crouched and ran readying a fist of energy only to have another telekinetic blast sent your way. You pushed through sending your own burst of invisible energy knocking the entity a few feet away. You fell in your knees weak, and your vision was already starting to fade.

"(Y/n)-san!"

Your eyes snapped open, and even though your ears were pounding you still heard his voice.

"Mob...?"

You felt two hands on your shoulders that shook you slightly. Blinking a couple of times you saw Mob, with a slight concerned expression etched onto his face. If you weren't close to unconsciousness, you would have been shocked. You never once saw Mob express emotion, at least from what you saw anyway. You felt Mob cradle you, but what caught you off guard was his blue glow. Your half lidded eyes widened slightly, for a split second you saw an absolutely furious expression. Right before your vision faded to black.
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A couple hours later you woke up uncomfortably on a couch. Your head had a slight ache, but it didn't compare to earlier how you felt. You shook your head and suddenly memories came pouring in like a river. Your head looked around in different directions at the unknown decor, if it hadn't been for Mob walking in the doorway your powers would have burst out over the shock.

"(Y/n)-san you're awake I see." Mob spoke out. You heard his emotionless tone back in his voice, and the blank expression painted on his face again.

"M-Mob..." You stuttered absolutely confused. He joined you on the couch.

"I suppose you wanted answers. But I'm hoping you will answer my questions too." He said. You just nodded in agreement.

"Mob, you're an esper aren't you?" You asked out of the blue, he took a moment before nodding slightly.

"Yes. I am." He said bluntly.

"And I saw that you're one as well (Y/n)-san. Might I ask what your power is?" He asked in curiosity. Your cheeks turned pink as you saw he leaned closer that you could practically see it in his blank eyes. You rubbed the back of your head sheepishly.

"Uh, yeah. Energy manipulation. Although I use more Invisible energy."

"Huh, I've never heard of that before."

"And I'm guessing you're...Telekenesis?" You guessed poking his sides. You could feel him tense slightly which amused you.

"A variation, but yes."

"Interesting..." You mumbled. You put your hand to your chin in a pensive matter and just stared at him. Mob felt a little creeped out, but he could also felt the heat rise to his face.

"Hmm..Mob?"

"Yes (Y/n)-san?"

"I want you to fight me." You stated directly. Mob was a little taken aback by your request.

"Why do you want me to do that?"

"Because...I'm curious. How strong are you. Before I passed out you looked like you could take down several buildings. It makes me feel excited. So come on!" You pleaded grabbing his hands and shaking them up and down. You have him a pouty, pleading look, and Mob just couldn't help but find you down right adorable. He looked away slightly.

"That's not a good idea."

"What?! Why?!" You asked in a whine. He sighed before locking his eyes with yours.

"Because you were just injured. I don't want to risk you getting hurt."

"But I won't get hurt. I'm a pretty strong psychic."

"(Y/n)-san I'm serious even if you are strong, I don't want to risk it." He said sternly. You sighed defeated leaning back on the couch, but you still smiled hiding it.

"Alright."

"But," Mob said making your head perk up slightly.

"Maybe. We can do something else? Like a race maybe?" He asked slightly unsure himself. You blinked for a moment before bursting out into complete laughter, even falling onto the side of the couch.

"Sure!" You said recovering and punching his shoulder lightly. Mob's eyes twinkled slightly before nodding at you. You got up ready to leave, getting in a good stretch.

"Oh by the way.."

Mob felt a light, light pressure on his cheek. His eyes glanced slightly seeing your face very close. His heart beat fast, and it took a lot of willpower for him not to blush heavily. You grinned waving out the door.

"That's a little thank you for saving me!" You exclaimed running out the door.

Mob leaned on the couch still in awe and shock. A first kiss from a girl...

A dream like look entered his eyes as he felt his own heart racing. He couldn't wait to see you again.

A/N: I'm so tired. Honestly I'm losing my edge with one shots and writing in general. But anyway, requests shall still be slow. A little explanation on Invisible energy manipulation: Basically the psychic can take undetectable energy and create, shape, and manipulate it to their will. It's like energy manipulation except it's Invisible. Like you can create force fields, energy bursts, etc. I'm very interested in esper powers so I do my research.