Birthday Party Reward~

Izuku woke up in the morning and stood up and walked downstairs, not wanting to wake up Momo, as he went into the kitchen. He figured he could make breakfast for everyone but stopped moving because he saw his mom talking with another green-haired person.

"M-mom?" Izuku said, causing both to look at him as the other green-haired person stood up and smiled at him. "Izuku, you don't remember me?" The green-haired person said, "Should I? I don't know you." Izuku said. 

She had tears in her eyes as she spoke, "Izuku. Is it me, your sister, Izumi?" Izumi said, "Izumi?" Izuku said, totally confused. "Yeah, it's me, your sister, Izumi. I've been away for so long. I'm so sorry," Izumi said as she hugged her brother, and he hugged back. "Why did you leave?" Izuku said.

"I wanted to see how you grew without me; I'm already your big sister, plus I'm older than you," Izumi said.

"How come the author didn't mention this?" Inko said as Izumi shrugged her shoulders, "Um, who's the author?" Izuku said, "Nothing important," and Inko said.

"Do you remember how we used to do the fun stuff?" Izumi said, "Um," Izuku said, and they heard Inko laugh. "Oh yeah, I remember the fun stuff; I remember catching you guys doing the deed," Inko said, embarrassing them both.

"Izuku, who is she?" Momo said, coming from upstairs, "Oh, uh, Momo! This is Izumi! My sister!" Izuku said, pointing at his sister, "Oh, hello! "Momo Yaoyorozu, Izuku's girlfriend, nice to meet you," Momo said, holding her hand out. "I'm Izumi Midoriya, this nerdy sister," Izumi said as she shook Momo's hand.

Izumi hugged Izuku from behind and spoke to Momo, "You mind if I join the harem, Momo?" Izumi said, "Yeah, sure, but wouldn't it count as incest?" Momo said, and Izumi waved her off. "Come on, Momo, he's the only male in Japan, and plus, he's a tall guy; most guys are like 5'4 or 4'1 these days," Izumi said, recalling a news article from somewhere she read. "Yeah, that is true," Momo said, "plus, he is packing a big dick as well." Izumi said, making Izuku beet read, "I can't argue with that," Momo said.

"Izuku, you're 17 now, right?" Izumi said, "Yeah, I'm 17." Izuku said, "Hey, I still remember how we almost did it at 15 years old."

"Wait what?" Momo said, "Oh girl, let me tell you a story," Izumi said as she gestured for Momo to sit down, and Izumi placed Izuku on her lap. "I'm not a kid anymore, Izumi," Izuku said, and Izumi shrugged her shoulders.

"I remember the day like any other day," Izumi said. "I always remember that you were always so clingy towards him, much like seducing him as well." Inko said, "Oi, I learned it from you." Izumi said.

Inko was tired of saying something, but words didn't come out of her mouth.

"Now let me tell my story!" Izumi said, "Oh, and before the author forgets, I'm 2 years older than my brother, while he was like 13 at the time, while I was 15."

3 years ago

We see Izumi holding her brother after a rough day he had with Katsumi. "Izu, you need to tell her to stop," Izumi said, healing him with her quirk and making some of the burns go away. "Sorry, I don't really have that confidence in myself," Izuku said as he looked at his fully healed arm. "Even if you have a super regen quirk, it has its limits," Izumi said. "Yeah, yeah, I know."

Izumi looked down at his crotch to see a bulge coming out of his pants, and she smirked, knowing full well what it was since Inko was teaching her about that stuff, and she reached down and touched it, making Izuku jump. "Izumi, what are you doing?" Izuku half mumbled, seeing as Izumi was holding her hand over his mouth. "Your little guy needs help, plus I think you'll like this," Izumi said as she reached down and pulled down his pants to see a 6 in. and a half-inch dick. "W-whoa," Izumi said as she tried to touch them, but Inko came into the room and spotted them. "What are you doing?" Inko yelled in shock, and Izuku and Izumi were both startled and looked at Inko.

Now 

"That's about it," Izumi said, "huh." Momo said, "Well, I guess you guys went to the entrance exams, right?" Izumi said, and she looked down at her brother. "How did you do?" Izumi said, "We did really great, I think." Izuku said, "Yeah, we did. Now we have to wait for the mail to arrive." Momo said.

"Right," Izumi said, "I might come live with you if there are dorms there, Izuku. After all, your sister might need to heal you." Izumi said, "Okay." Izuku said.

'Huh, Inko was right when she said she was clingy towards him' Momo thought. 

"Oh, that reminds me, you guys were taking the entrance exam, right?" Izumi said, and Izuku and Momo nodded. "Just to let you know that I'm properly going to be working at UA soon, since I'm an underground hero after all," Izumi said.

"Wait, you're an underground hero?! How come I didn't know?" Izuku said, "I've been working on my stealth with a certain someone, so now I don't get recorded when stopping bad guys."

"Oh," Izuku said.

"Well, Izuku I gotta get going soon; I need some work soon; plus, isn't your birthday soon?" Izumi said, and Izuku nodded.

Izumi sits up and places Izuku on Momo's lap as she walks out of the house.

"Well, that was interesting, don't you think?" Momo said, "Yeah," Izuku said through his flustered face.

A week passes.

"Happy birthday, Izuku!" Inko said as she took out a cake from out of nowhere, "Where did you get that cake?" Izuku asked, and Inko moved her finger around. "A mother never tells her secrets," Inko said, placing the cake down. "Oh, and Izuku, my parents are coming as well, as is one of my friends." Izuku heard Momo say, "Okay."

Izuku's eyes bulged out of his eye sockets as he turned around to see Momo. "Wait, your parents?! I never met them! Oh god, oh god!" Izuku said packing.

"Don't worry, I'm sure they will like you," Momo said, placing a hand on her cheek. "I hope so!" Izuku said, and there was a ring at the door. Izuku opened the door to see the Bakugou family. "Hi, Aunt Mitsuki! And Kachan! Wait, where's Uncle Masaru?" Izuku said, looking at them.

"He's just working right now and couldn't come," Mitsuki said as she held up a gift. "But he did tell me to give you this!" Mitsuki said as Izuku took it from her, "Oh, really? What's in it?" Izuku said, "You have to wait until you can open your present, young man." Inko said, "Ah, sorry!" Izuku said as he quickly put the present down, "Oi nerd, I got you a present," Katsumi said. "Oh, really?! Thanks, Kachan!" Izuku said as he took the present from Katsumi, who had a small blush on her face.

"Sorry if I'm late," somebody said, and Izuku turned around to see Sorahiko. "Sorahiko, I didn't know that you were coming here," Izuku said.

"Well, I wanted to be a surprise," Sorahiko said as she handed Izuku a present, and he placed it down on the table.

"Oh, who's this?" Mitsuki said, "Oh, I'm Sorahiko Torino, his trainer. Nice to meet you," Sorahiko said as she shook Mitsuki's hands. "Oh, and Izuku," Sorahiko said, and Izuku turned towards her. "Yes?" Izuku said, "Someone special is going to come," and Sorahiko said, "Eh?" Izuku said before Sorahiko moved out of the way, as all might came through the door with her hero costume on. "I AM HERE!" all might said.

Katusmi almost fainted seeing her favorite hero here. "All might!" both Izuku and Katsumi said, as well as Momo.

"What is all you might be doing here on my birthday?" Izuku said, "Well, your sister gave me your birthday date, so I thought I'd stepped by!" all might said.

Katsumi turned her head to Izuku and whispered, 'I didn't know you had a sister." Katsumi said, "Well, she was always homeschooled, so that's why." Izuku whispered back, and Katsumi turned her head back. "Ah," Katsumi said.

"Well, young Izuku, I have a present for you as well!" all might said with her voice booming, "Oh, really?" Izuku said as he spotted a pretty big present on her arms, "What is it?" Izuku said as all might gave her present to him, "Its a surprise!" all might said.

"Now let's eat some cake!" Inko declared as she cut Izuku's birthday cake after singing happy birthday to him.

Mini skip 

"Alright, Izuku, you can now open your gifts," Inko said to her son as she floated over a pretty big-looking cake and sat it down on the floor. "Huh? Another birthday cake?" Izuku said as he stepped closer and licked the icing. "Uh, pretty good icing," Izuku said.

Suddenly, Izumi popped out of the cake, splattering some cake everywhere. "Oh god!" Izuku said, being scared to be deaf, as he looked at Izumi, who was naked....and his brain turned off.

"Happy birthday, Izuku! I hope you like my birthday suit!" Izumi said as she happily jumped up, "Wait, your the nerdy sister?" Katsumi asked, "Yeah." Izumi said, "Holy sh*t, you're huge." Katsumi said only to get bonked on the head by Mitsuki, making Izumi giggle.

"No, I'm not getting it; you're bigger than ink! What the hell?" Katsumi said. 

"That is true; my mom is only 9 feet tall; I'm like 10 feet taller than most girls anyway. I think it has to do with my genes," Izumi said as she stepped out of the now-destroyed cake and watched her brother giggle, seeing him shocked.

Izuku quickly snapped out of it. "W-why a-are you n-naked?" Izuku said, "Well, I wanted to surprise you since you know you are 18 now." Izumi said, "H-huh." Izuku said.

Izumi puts her hand under her cleavage. "Don't worry about me; just continue opening your gifts," Izumi said as she stepped closer to Izuku and whispered, 'Don't worry, we'll have some fun later. Izuku choked on air for a second before composing himself.

The presents were:

A book for training by Masaru

A limited edition (Izuku was happy at that to have it in his collection)

Some training gear with weights that weigh like a truck.

When Izuku got to all his might, he opened the box to see... a hero costume? Not just any hero costume; it was Toshinori's original costume when she first debuted in America, and Izuku cried like a waterfall of tears. "A-all might! I-i-i-i-i-i-i can keep this?" Izuku said as he was holding her costume.

"Of course, young Izuku," all might said, and she whispered into Izuku's ear, "it's okay for you to keep it, plus I don't know what your sister said, but as your reward for doing so great these past months, I might reward you with something special." As Izuku looked at her, she was confused at first but got flustered quickly.

Timeskip 

"Sorry if we were late to the party," somebody said after Momo let them in, and Izuku turned around to see Momo's mother and her other mother. 'Two mothers, huh? Izuku said in his mind, and he saw Momo gesture them over to him. "You must be our daughter's boyfriend; my name is Kimi Yaoyorozu," Kimi said, and Izuku turned to see the other mother. "My name is Jaclyn Yaoyorozu," Jaclyn said.

"Nice to meet you as well; my name is Izuku Midoriya," Izuku said to the mothers of Momo. "He's a keeper, right, Kimi?" Jaclyn said, "Yeah, Momo dear, please keep him safe." Kimi said, "Yes, mother, and Momo said.

After the party

Momo had to leave because she wanted to train for the upcoming week for UA, even if they got in. Izuku sighed as he turned around after saying bye to the Bakugo's and Sorahiko. "Alright, I.z.u.k.u~," Izumi said as she tapped his nose. "Young physicist, who wants to go first?" Toshinori said in her civilian form, and Izumi put her finger on her chin. "Hmm, I'll say you go first, Toshinori; besides, I think he can get good experience." Izumi said, and Toshinori nodded and started to strip down. "Wah! Toshinori?!" Izuku said. "Y-Izuku, you need to have experience in sex in general in order to have more girls in your harem, so this is a good experience for you." Toshinori said.

Once Toshinori finished stripping in front of Izuku, he noted that Toshinori's breasts were a bit smaller than his sister's breast, which was larger than Momo's breast, and that's saying something.

"Shall start?" Toshinori said as she gently sat Izuku down on his bed, 'I need to talk to him later about my all-power shrine. Toshinori said as she pulled down his pants, and a 9-inch dick came out of his pants. Toshinori was surprised at the size of the dick she was seeing.

' I-it grew?!' Izumi yelled in her mind.

Toshinori regained her composure and gently pushed Izuku down on his bed. 'Oh, I see, Izuki said as she got on top of the bed and sat on his face.

Izuku's Pov 

I saw Izumi get up from the floor and get onto my bed, and her pussycat was right against my face. "You have to lick it, Izuku," Izumi said, and I started to lick it, and I felt my dickens being sucked on. This is all so overwhelming! I think I might die tonight.

After a while,

"Sorry for spraying my cum on you, Izuku," Izumi said, handing me a tissue, and I whipped my face with it. "No worries, no harm done," Izuku said.

After I came inside Toshinori's mouth, she started licking it again, cleaning it. "Alright, young physicist, it's your turn," Toshinori said.

Izumi laid on top of me, and I felt Toshinori's hand grab mine and stick my fingers inside her pssy. "Toshiori?" I said to her, "*moan* Izuku, just keep on doing this, alright?" Toshinori said, and I obliged and did it anyway.

Izumi, however, just pushes her pussycat onto my dick. "Uwa, I've been waiting for this~" she said, and I gave her a deadpan look. She sent a glare at me, and I shrugged, and she moved her hips. "Doesn't it mean that you're no longer a virgin?" Izumi said, "Wait... oh, fuck your right," I said.

"How come I never noticed it before? This is what you meant, right? Having sex with your own brother—is that even allowed? Is someone going to call the FBI on us? OH GOLB!!" I said, and Izumi slapped me. "Get a hold of yourself. Of course, no one is going to judge us. I mean, come on, in Japan, you are the only boy. If the government says that you can have sex with anyone you think is wrong to be with you in your home, then that counts to me, right?" Izumi said, and I looked down. "I guess so," I said. "Good, now let us have fun," Izumi said.

She kept riding me, and after a while, "Izumi, I'm close! Get off!" I said, "Nope, you're going to have to *moan* force me off." Izumi said, her hips smacking against mine as she moved a bit harder. I grabbed her shoulders and pushed her down, and I felt a wave of pleasure as I ejaculated onto Izumi. "Huh, so this is cum," Izumi said as she licked the white stuff. "I-Izumi," I said, really tired. I let darkness overtake me as I slept.

I woke up with my head hurting. "Ow, ow, ow!" I said, clutching my head. "What... is this?" I held my head in pain and my face toward the window as the pain got stronger. "It's... over... there!" I said as I jumped through my window, breaking it in the process of leaving, and jumped on the buildings where the pain was coming from.

Ryuko's Pov 

"Ack!" I fell to the ground, not able to move as my dragon form dissipated. "You are a tough one, Ryukyu." Hero Goroshi said, "I won't let you kill other heroes!" I couldn't move. 'Is this her quirk?' "It's such a shame, really; you are a good hero, Ryukyu, an excellent hero indeed, but you came after me to protect other fakes, right?" Hero Goroshi said, I cried out in pain as she stabbed one of my broken wings. "I won't let your efforts be in vain, though I'm sorry to have to do this," Hero Goroshi said as she lowered her sword. 'Is... this... ho... die?' As I closed my eyes and let out a tear, "SMASH!" I heard somebody say, as I looked up in shock, "Don't worry, Yukyu! I'm here to save you!" He said, "N-no! "Please! Get out of here!" I tried to get up, but I fell to the ground again. "Don't worry," he said as he gave a thumbs up. "Hmmm, a boy protecting a girl? You know, if you do this, then you might die." Hero Goroshi said, "Then... I'll accomplish my goal, to protect other people's smiles, to make sure that they are saved with a smile on my face," he said, smiling as he raised his hands up and started to glow with lightning coming off of him. "A boy with a quirk? This is interesting," Hero Goroshi said, smiling.

The boy rushed at her as he dodged a strike coming from the left: 'He's fast!' I looked on and saw him punch the hero Goroshi in the head, and I gasped, "You're good, but not good enough!" Hero Goroshi said as she swiped her sword to the left and as he jumped into the sky and punched her in the face. "Hmm, I won't kill the both of you, but next time, Ryukyu," she said, looking at me. "Don't get in my way," she said as she left by blinding us with a bright light, and I looked again to see that she was gone.

The boy came up to me as he lifted me up to support me, and we started walking. "You don't have to do this," I said to him as he just smiled at me, and I blushed as I looked away. "No, I want to ryukyu," he said. "What's your name?" I said to him, "Izuku Midoriya." Izuku said, "T-thank you for saving me, my hero."

I spotted all the people coming towards us with a worried face. "I got a call! From some nearby heroes! Are you okay?" All might said, rushing towards us, "We're fine, all might." I said to her, "Your wing, Ryukyu." All Might said, "The recovery girl can heal the damage." I said to All Might, "What exactly happened?" All Might said.

After a minute of explaining, and out of nowhere, all might hit Izuku in the head, "Wow!" Izuku said, "What the hell were you doing, Izuku?" all might said, "Eh?" Izuku held his head in pain. "Oh, I was feeling a sharp pain in my head, and by the time I got there, I saw Ryukyu getting almost killed. How could I not step in and help her?" Izuku said, screaming at all might, "What's the point of being a hero if you're not meddling in things you are not supposed to do? I want to be a hero and be there for everyone." Izuku said, and all might pat his head, "I'm not mad, I'm just proud, Izuku." "Ummm, how come you are calling him by his first name?" I asked, kind of angry, "Oh, me and Izuku know each other, and also, the hero commission tasked me with protecting him, so we got to know each other, so that's why," all might said.

"Let's get you to UA," you might said.

Timeskip 

"That was very dangerous, young man, but I can't take you like this idiot did here," Chiyo said as she hit all her might in the face. "Wow!" All might said, "You better be glad I didn't tell Sorahiko, or else she might beat you to the ground!" Chiyo said, and Izuku, and both might shiver and fear.

"You are fully healed, dear, but you have to stop hero work for a while in order for your wing to be fully healed," Chiyo said.

I nodded, stood up, and turned to Izuku. "As for thanks for saving me tonight, take this," I said and leaned forward, "chu~" I kissed him on the cheek and left.

No one's pov

"Well, another one added to his harem," all might said, "huh?" Izuku said "but all might all she did was kiss me" Izuku said "well besides that you were her hero tonight, a knight in shining amor if I might add" all might said as she picked up Izuku "now let's get you home!" all might said as she leaped of from the window.

Once all might got Izuku home, he laid on his bed and fell asleep.