It has been four years since he was reborn in this world. Mokami, for the most part, got used to living in a big mansion with lots of maids, a truly caring mother, an adorable/annoyingly cute sister, and a bastard of a father.
He learned the background of his new family better as he lived his days. For starters, his father, Yozo Yaoyorozu, owned a big chunk of I-Island's shares with other side businesses. So it was safe to say that they were filthy rich. So rich that even if they stopped all their money-bringing activities and lived a life of debauchery, they would still have money for the next generation. Of course, being a greedy bastard, his father thought differently and still worked every day, and ignored his family. It was cool because Mokami hated the guy, so the less time he spent with him was better. Instead, he focused all his effort on his mother and sister, and truly connected with them.
Momo accepted him as a big brother, and called him Onii-chan, as soon as she learned how to pronounce it. Although in early years, she called him Omi-cha, Moka-cha, and other cute names as she couldn't pronounce the words, Mokami couldn't recall those days without going full session of adoring. Since the status quo was established, it was Momo who followed Mokami around and learned from him. He didn't know why, but he was always respectful to servants in the mansion. His mother was polite and his father was outright rude to them as if he was their master, but since Mokami was truly respectful, Momo learned from him and never disregarded them, making all the servants truly appreciate the duo.
Mokami, from time to time acted like a child, but he didn't find it odd. He knew he had a past life, but he knew almost nothing about it. How old was he? What was his worldview like? What was his gender or sexual orientation? He knew nothing. He could feel that he was male and he was straight, but nothing was certain, thus, growing up as a baby, he thought it was normal for him to act like one from time to time. Although he was more mature due to all the information stored in his mind, it was perfectly normal for him to act his age.
This also covered his wants. He felt love towards his mother and sister, and he knew there was something more deep inside him. The idea of having feelings for a child put him off for a long time, but he was a child as well. Not like he wanted to have sex. He just felt really close to them, and might consider more as they grew up. Not like he was an adult whereas the other party was a child. Sure he was more knowledgeable and mature, but that didn't mean he was preying on them.
From the day he realized he was in My Hero Academia World, he knew he would want to fool around with many of them. When he first saw Inko, that urge blossomed deep inside of him. And as he grew up, he started to have these feelings for others as well.
His mother, Mika, was also the cutest mother a child could ask for. Although it was certain by now that his father married her for her beauty, she wasn't stupid nor useless in any sense. She had a company of her own that produced jewelry by altering valuable stones' molecular structures. It was a downgraded version of Momo's quirk. Although she couldn't change the dirt into diamonds, she could pretty much purify valuable minerals into purer forms. By buying gold, diamond, emerald, ruby, and such shiny stones and increasing their quality, and forming them into beautiful accessories, she created a solid business. Compared to Yaoyorozu fortune, it was a drop in the ocean, but compared to a 9-5 everyday worker, she was filthy rich.
The bastard father, on the other hand, had a tad different quirk. He could enhance his body by using fat in his body. The most obvious usage of this quirk was enhancing the muscles, but it took too much in the return for too little, thus, the bastard used it to enhance his brain and neurons to exalt his speed of thinking. That was how he excelled in business and created a fortune. Though it was grandpa Yaoyorozu paved his path by owning a big piece of I-Island. Otherwise, even with an enhanced brain, the bastard couldn't do much.
Quirks were mysterious in that sense, they could be used in many ways. Lucky for Momo, hers manifested in a combination of two, allowing her to create anything, anything non-living by using fat stored in her body. Mokami was worried if his power would be the same or not, as he was not a character in the series, but for the last four years, he tried not to ponder over it too much. But lately, his worries only increased, because Momo awakened her Quirk just a night ago.
"Don't worry Moka-chan, girls mature earlier than boys, so it is normal for Momo-Chan to awaken first. I am sure yours will too, soon. When it does, I will take both of you to the doctor together. Since hers is not dangerous to the environment or herself, I will wait for a while. " Mika said with a reassuring smile.
"I hope so, Kaa-chan," Mokami said sweetly, making his mother hug him. Her hug and words did reassure him, after all, both he and Momo were tested when they were born and they didn't have the extra joint in their pinkies, a big proof of the existence of quirks. And much to his relief, he too awakened his quirk later that day.
As he was sitting with his cute little sister, coloring with crayons, Momo asked for a red one. Looking around, he failed to find one and realized it was probably all used up last time as it was Momo's favorite color.
"Onii-chan, red! " Momo started to cry, as he explained there wasn't one at the moment. In frustration, he willed and a crayon appeared in his palm. The sensation was sublime. Not the sensation of using Quirk, no! Willing something and creating it. For the first time ever, he felt bigger. In a sense of being, he felt he was above others. He didn't know if it was because of his past self or if it was because of his Quirk, altering his character, but he couldn't lie to himself. He felt divine. But as it was a pressing matter, he grabbed the crying Momo and run to his mother with the crayon in his hand.
"Kaa-chan, I awakened! I awakened my Quirk! " He shouted as he run. Soon, everyone was gathered. Servants were happy, and his mother was smiling brightly. "I created this! " He beamed as he showed the almost disfigured poor thing in his hand from his excitement. Realizing what was going on, Momo ceased to cry and smiled too.
"My little geniuses. Both of you awakened the same, Quirk. You are amazing. " Mika hugged the duo and ordered the chauffeur to ready the car. In no time at all, we were taken to the private hospital and were taken in by a beautiful nurse who coincidentally was Inko Midoriya again.
"Ara~ Mokami-chan, Momo-chan! " She cried out as soon as she saw us and came to give the duo a hug. At the time, she was still beautiful in her skinny form. From the show, he knew she would get depressed when she realizes Izuku has no Quirk and will gain weight over time, which was something horrible.
"Inko nee-chan, you are still as pretty as ever," Mokami said with the cutest expression he could muster. He subtly planted these ideas to prevent her from letting go. After all, she had a connection with the family and would visit often. Although he still didn't know what this connection was. She was there during the delivery, and would visit from time to time with the midwife, who he later learned was actually an expert in medicine and was on Yaoyorozu payroll to do regular check-ups. With her healing-related Quirk, she worked for the family for years.
"Aww! You are still the cutest! " Inko pinched Mokami's cheek, as she looked at him with stars in her eyes.
"Ahem, Inko, is the doctor in the room? " Mika asked frowningly.
"Oh yes, Mika-san, she is waiting for you. " She answered embarrassedly, as she opened the door. Mika took the children in and greeted the old lady sitting behind the desk. As the trio entered, Inko announced from the entrance and closed the door.
"Yaoyorozu-san, I heard the good news. " She said as he looked at the boy and the girl.
"Yes, Higuchi-san, Mokami too, awoke a few hours ago," Mika answered as she patted him on the back of his head.
"Good, good. Let's test them then. " She said as she conducted several tests. And to say that they were elaborative would be an understatement. She even tested how much fat tissue Momo and Mokami used when creating different things. Which begged the question, how did Momo and Mokami create things in the first place?
In Momo's case, when she first awakened, she was playing with toys and created a missing puzzle piece. In a sense, it was a simple concept. Although the duo were small, they still knew the chemical formula of some of the things since Mika strongly believed that the children would inherit a Quirk similar to her own, thus she taught them simple elements and compounds. Surprisingly, the Quirk didn't require its user to understand the chemical reaction, just the knowledge so the fat could be converted to said atoms and then to elements and from there to compounds.
It was understandable, although given her young age, it was a miracle. But in Mokami's case, he created something he shouldn't know of, but he did. How? Easy really, there was some information about crayons in one of the fiction stored in his mind. He didn't retrieve this information willingly, in his distress, it just came to him. And there be the crayons. The process was also different from Momo's. At first, he didn't realize it, but when he thought about it, he could feel it. After all, the power was part of him and it was explaining to him that he could do much more.
…The non-living restriction Momo had, didn't apply to him.