(A/N: Retconned MC name to Hiroto instead of Saitama.)
[MC POV]
It's so comfortable here. I don't know where I am, but it's really dark. I try to move my body but found extreme difficulty in doing so.
Wait, if I were to think logically, after being reincarnated you would naturally have to be birthed. It seems that I'm inside of my mother's womb, but… how long would I be stuck in here for? Not that I mind, it really is comfortable and warm.
As I begin to drift off to sleep, I can hear some muffled sounds with a faint light passing through my closed eyelids. Ah, it seems my time has come.
Hello, world.
[3rd POV]
"Ahhhhhh!!!" A woman's scream echoed throughout the room, as she held her husband's hand in a death grip to deal with the pain of giving birth.
"That's it, honey, just breathe. Come on, follow me. 1… 2...1…" Her husband tried to reassure her and ease her pain, but his wife was in too much pain to care.
"You did this to me!!" The wife screamed at her husband. "Arggh!! I'm gonna get you back for this! 'Let's make a baby' he said, 'it'll be great' he said! It hurts so much!!"
The husband smiled warily and looked at the doctor for help, but was completely ignored. "Keep pushing and stay strong, I can see the head already. He's almost here." The doctor said as she helped with the delivery.
More curses were being flung around, but eventually started to die down as a baby's scream was heard.
"Waaahh!"
"Ah, my baby boy!" The mother said tiredly as she reached her arms towards the doctor. "Let me see my baby boy."
Cradling the boy in her arms, she lovingly looked at her son. "My little Hiroto."
The baby raised his little arms as best he could and opened his eyes.
[Hiroto POV]
So that's my mom, huh? Well, I never knew mine back in my first life. The way that she's looking at me feels nice, different than how the orphanage caretakers would look at me.
Where's my dad then? Ah, that must be him wearing glasses. Why is his hand bandaged? Oh well, I'm getting tired. Time to sleep.
[3rd POV]
After a week had passed, Hiroto was currently in his crib early in the morning.
'I don't feel like I'm strong. Do I have to wait for my 'quirk' to awaken to be able to get the powers?' As these thoughts rang into his mind, a familiar voice rang through his head.
"Bzzt. Hello? Can you hear me? Well, of course, you can, cause I'm God! Well, I hope you're enjoying the first week of your reincarnation, Hiroto. I sort of forgot to mention when you would get your powers and the hair loss that comes with it." God's voice echoed in his mind, as a little hummingbird manifested itself on top of Hiroto's crib.
"Quite cool, right? I remember that the Olympians like to use this trick quite often. Quite arrogant though, those guys. Had to wipe them out, but that's a topic for another time." The hummingbird hopped around on the railings around Hiroto.
'Uhm, I don't think I was supposed to know that, but whatever. So, what's this whole thing about my powers?' Hiroto asked in his mind.
"Well, if you want to awaken your powers, it's quite simple," God said.
Hiroto nodded his little head. 'Ok, what do I have to do.'
God cleared his throat and said in a serious and deep voice. "100 push-ups! 100 sit-ups! 100 squats! And run ten kilometers! Everyday!!"
Hiroto stayed silent for a second, before shouting in his mind, 'Isn't that just what Saitama did anyway?! If it's his training routine, you won't have to worry, it's already been embedded into my mind since I'm now Saitama.'
"Oh yeah, there was that. Well, I just came to tell you that and not to slack off if you want to achieve your powers. Of course, you won't be able to do it now since you're just a baby. So give it a couple of years before you can properly train, then you'll just have to stick to your training regime no matter how much you feel like dying."
Feeling the pressure, Hiroto nodded his little head, "I'll keep it in mind."
"Alright, that's all from me then. Have fun with your new life!" God said before the hummingbird disappeared in a golden puff of light with particles floating around the room.
'Well, for now, I'll just have to wait till I'm older. Then, when I'm ready to train, there's no going back.' Hiroto thought, balling his tiny little fists until he couldn't control his own bowels as a foul stench filled the room.
"Waaahh!" Baby Hiroto cried out, having been bested in this battle already. The next few years are going to be a long and arduous journey.
[Time Skip]
10 years had passed since Hiroto was born. Currently, he was inside his room doing the last of his 100 squats. He wasn't when, but apparently God had paid a visit and modified his child body a bit, making him be able to do the training regime as early as age 7 since he would have needed to wait a lot longer until his body was able to support it.
"Huff… 98… 99… 100!!" Hiroto cried out, as he clenched his chest and breathed heavily. Pushing his shaking body, he sneaked into his dad's office where a treadmill was stationed. Since his dad owned a gym, he had his own training equipment at home as well.
A few hours later, Hiroto finished his run and collapsed on the side of the powered treadmill as it powered down. It's been exactly a full year since he started this hellish hero training regimen.
"I really am going to die at this rate," Hiroto muttered to himself, as he wasn't able to move a muscle currently.
Currently, his looks were similar to that of the Original Saitama from One Punch Man, except much, much younger and still with his short black hair. He had sharp eyes and facial features and could be considered attractive. Of course, this was before he would have gotten his powers...
"Well, no point in laying around all day. I better get up before mom finds me and nags me again." Hiroto muttered to himself. Once, he was caught by his mother performing the extreme training and was rebuked, saying that a young child at my age shouldn't be doing something so extreme.
She of course blamed it on her husband, saying that I was affected by his muscle headed genes.
"Well, it seems you actually stuck to your guns and didn't give up for a full year." Once again, a familiar voice entered his ear, as Hiroto looked towards the couch in the room and saw a ferret sprawled lazily on it's back.
"What are you doing here, God? Don't you have some Godly dutied to attend to?" Hiroto said as he gulped down an entire bottle of water.
"Well, it's time," God said as the ferret's eyes gleamed a golden luster.
"Huh? What do you mean?" Hiroto said, but suddenly felt dazed as he tried to get his bearings. The room started to spin as he felt his head being pounded by hundreds of trucks at once. (A/N: Truck-kun strikes again! jk.)
Collapsing on the ground, the last thing he heard was his mother's shriek, as the ferret in the corner of the room disappeared.
After a few more hours of his mother screaming and his father being scolded for some reason, Hiroto finally awoke in a hospital.
Opening his eyes, he saw his parent's concerned look as they were talking to a doctor. Seeing her son wake up, Hiroto's mother quickly pounced on him.
"Oh, my baby boy! How are you feeling? Are you hurt? Do you feel strange anywhere?" His mother said as she checked over his body.
Hiroto shook his head and said, "I'm fine. Actually, I feel a lot better than ever." Hiroto looked at his parents as he stretched his arms around.
Suddenly, something just clicked in his mind. He slowly and anxiously reached his hand up to his head under his parent's worried gaze.
What he expected to feel, never came, as all he could feel was his naked and bald head. The doctor had a complicated smile on his face as he approached Hiroto and his parents.
"I understand how anxious you would feel right now. The moment you arrived here, your hair had already started to fall off. I'm afraid that you might stay bald, as this might be an effect of your quirk manifesting." The doctor explained.
"His quirk?" Hiroto's father said, looking at the doctor who nodded his head.
"Usually, when someone's quirk manifests there's a chance that he may undergo some sort of physical transformation. There have been people who had gained tails, grew another eye, or grew hair over their entire body. In this case, it would seem that your son lost his hair as a result of his quirk manifesting." The doctor said.
"But, he never had a quirk up until now. Weren't quirks supposed to manifest by the age of 4 at the latest? How did it manifest now, at all times?" His mother asked, worried that there might have been something wrong.
The doctor shook his head and said, "I'm not sure either. It's rare, very rare, but people have been able to manifest their quirks at a much later stage in their childhood. You could associate him as a late bloomer.