Flashback...
Kousuke was 12 years old; his hair was worn in a lower ponytail. He wore a buttoned downed white shirt with black pants and shoes. He was known as the Tiger of Moroki junior high school. He was still in 6th grade when he saved older high school girls from a group of 1st-year high school students. After a few days, the leader of the white fang delinquents, the third year in Kanazuki High school, heard about Kousuke from minions.
On his way home from school, he was surrounded by 1st, the 2nd and third years of Kanazuki High school. Yukiya was with him at the time. Some of them had weapons and wore masks. They all wore black Gakuran uniforms.
"HEY, YOU BASTARD, HOW DARE YOU INJURE MY LACKEYS LIKE THAT, YOU FUCKING BRAT," the leader shouted.
Kousuke smiled, and the leader blushed.
"There sure are a lot of you coming after a little kid like me," Kousuke said with a toothy grin.
"Brother," Yukiya said.
"My little brother has nothing to do with this; let him go."
"Fine, if we beat you, I will make you mine," the leader said.
Kousuke looked confused.
"Make me yours," Kousuke asked with a dumbfounded look.
"My name is Umehara Akaito; I am the leader of the White fang delinquents of Kanazuki high school. Your name, brat."
"Kageyama Kousuke, 1st year of Moroki junior high school."
"He's the Tiger of Moroki Junior high boss," one of the first years shouted.
"I know, he's supposedly one of the strongest people there, how interesting. Hey, smaller brat, get out of here; we're only here to teach your brother a lesson for messing with us," Akaito said with a smile.
"Yukiya, you're in the way stay. Get far away enough where you can still watch me kick their asses."
Yukiya ran further away from the crowd of students and watched from afar.
"Go," Akaito shouted.
They began charging at Kousuke. Kousuke blocked the incoming attacks. He punched one after the other as he stopped and dodged the others. After about two minutes of the fight, half of the guys there were on the ground unconscious, and Kousuke was still standing and barely tired.
"You have to do much better than that," Kousuke said.
Two of them took out knives. The rest of them charged at Kousuke. The two that had the blades sliced near Kousuke's neck and stomach, and Kousuke held his stomach.
"What the hell do you two think you're doing? We don't fucking do that shit; what the hell is wrong with you two," Akaito shouted after punching both of them to the ground.
Kousuke was in pain, but he didn't show it. He took off his shirt to reveal the muscles on his body.
"This kid's ripped. What the hell," Akaito thought.
"Hey, that was pathetic, come on and fight me, all of you. I'll take you down and then I'll treat my wounds," Kousuke said with a smirk.
"He's a demon," they thought.
Eventually, all of them were taken out. The leader was on his knees.
"How are you so strong, Kageyama," Akaito shouted.
"I trained my body since I was really young. I had to be strong to protect my little brother and my family. I'm still not strong enough," Kousuke said.
Back in the present...
"Kageyama-sensei was even cool when he was younger," Yuma thought.
Eventually, Yuma finished his laundry and laid out the futon. He laid down and fell asleep. The next morning, Kousuke woke up. He sat up. He was feeling a lot better than the night before. Yuma laying on the futon on the floor. He walked over and kicked him.
"Hey, wake up, you have to go to school," Kousuke said before crouching down.
"He's not waking up, maybe I should shake him awake," he thought.
Kousuke reached for Yuma's shoulder. Yuma grabbed his arm and pulled him into his bed.
"Hey what the hell," Kousuke thought.
Yuma still had his eyes closed and he opened them. He saw Kousuke underneath him.
"Hasegawa," Kousuke said.
Yuma looked at Kousuke and his revealed body through the Yukata. He was straddling Kousuke and holding his wrist.
"S-Sensei," Yuma shouted before he let go and got off of him.
Kousuke sat up. He sighed as he scratched the side of his head.
"Hey, go to school, you idiot. Make sure your classmates listen to the substitute," Kousuke said.
"Yes, excuse me," Yuma shouted while running out of the room blushing.
"Hasegawa-kun was kind of cute," Kousuke mumbled.
"What the hell am I thinking, he's a student," Kousuke thought as he stood up while slightly blushing.
"This fever is making me think some weird things."
He shut the door and the image of Kousuke's chest was in his mind.
"Sensei's face was flushed and his skin was pale. His body was completely muscle, and his nipple was showing. Ah, sensei was too defenseless. He's too erotic," Yuma thought as he felt turned on.
"No, I got to go to school."
After Yuma got ready for school, he headed out towards the school. Kousuke returned to his bed after drinking some water and medicine.
A few days passed...
Kousuke was on his way to the school. He was carrying a bag with Yuma's tracksuit in it. Takeya saw him.
"Kousuke," Takeya shouted.
Kousuke ignored him and walked passed him. Takeya grabbed his wrist and pulled him back.
"Kousuke-chan, I haven't seen you in days, don't ignore me. Come on I'm having Kousuke withdraw," he whispered.
Kousuke punched Takeya and sent him flying. He continued walking to his class while being slightly pissed off.
He opened the door and the student saw him.
"Kageyama-sensei, you're back," Yoru said.
"Yeah, I wasn't well for a few days, I hope you guys were doing the work I left because we have a quiz for all subjects in two days. "
"HUH," they yelled.
"Don't worry, if you have been doing the work, your guys should be fine. It's not like you were humiliating the substitute and not completing any of your work," Kousuke said with an evil smirk.
"Ah shit," some of them thought.
At lunchtime...
Kousuke was eating onigiri behind the school. Yuma saw him back there and blushed.
"I still can't stop thinking about Kageyama-sensei in a Yukata," Yuma thought.
Yuma imagined Kousuke in his Yukata underneath him.
"Hasegawa-kun," the Kousuke in his mind said.
Yuma screamed internally as he covered his face. His face was like a tomato.
"I'm such a pervert," Yuma thought as he slammed his head on the wall.
Yuma regained his composure and Kousuke looked confused.
"Why did he slam his head against the wall," Kousuke thought.
"What's wrong, Hasegawa," Kousuke asked before taking a bite of his onigiri.
"Sensei, I love you, go out with me," Yuma shouted.
Kousuke choked on his food.
"Shut up, what are you trying to do, make me choke, "Kousuke shouted after coughing.
"Also, I don't date my students, also," Kousuke said.
"Sensei, please go on one date with me?"
"No, look I appreciate you helping me out when I was sick, but that doesn't mean that I will go out with you, idiot."
"You're so mean, sensei. Come on one date, please," Yuma said with a pout.
"He looks like a puppy, he's kind of cute. No, he's a student," Kousuke thought.
"No."
"Sensei."
"I said no didn't I," he shouted before smacking Yuma in the head.
"Ever since I saw you in a revealing Yukata, I can't stop thinking about it. Sensei, you're too sexy for your own good," Yuma shouted while blushing.
Kousuke had a slight blush as he looked pissed off.
"Shut up," Kousuke shouted before punching him.
"Sensei, come on please."
"Shut up and listen. This constant declaration of love is not going to go in your direction if you keep pestering me to go out with you. I do appreciate what you did the other day, but that doesn't mean that I will fall in love with you."
"Sensei."
Kousuke sighed.
"I'll give you a reward for helping me out. As long as it's not about dating me or anything sexual, I can handle it," Kousuke said while looking away from him.
"A kiss," Yuma said instantly.
"Huh?"
"A kiss, please," Yuma shouted.
"Why do you want to kiss your teacher?"
"Please, Sensei," Yuma asked with puppy dog eyes.
"Cute," Kousuke thought.
"Fine, one kiss."
"Really."
"You need to leave me alone after though," Kousuke shouted while blushing.
Yuma grabbed Kousuke's shoulders and pinned him against the wall. Kousuke felt surprised.
"Hasegawa, now?"
Yuma lifted Kousuke's chin and kiss him. It wasn't a short kiss, it continued for a while before Kousuke punched him.
"Don't you think that's long enough," Kousuke shouted while trying to recover his breathing?
His face was really red and he had tears coming out of his eyes. His mouth had drool coming from the corner of his lips. Yuma's heart was beating a million miles a minute after seeing Kousuke's expression.
"Sensei, you're too erotic," Yuma shouted.
"Huh, what the fuck do you mean by that," Kousuke shouted.
"Sensei?"
"That was my first kiss, you idiot," Kousuke said.
"EHHHHHHHHHHHHHHHHHH," Yuma yelled.
"That was your first kiss," Yuma shouted before backing away from him.
"Yeah, shut up, idiot."