Chapter 1: Once Bitten, Twice Powerful

In a world theoretically exactly where we are today, the population of Earth has evolved to develop superpowers known commonly as "Quirks". These powers can range from powerful, to weak, and from odd, to mundane. It affects around eighty percent of the population currently, and a popular job to have in such a world is being a professional hero.

But what if we told you, that natural development of a quirk, isn't the only way to get a power...? Let's begin shall we?

In the city of Mustafu Japan, in the brush of some sidewalk shrubs, a small serpentine creature weaved its way from inside the bush it was hidden in, to the sunlight.

The snake was barely five inches long and had prickly white scales all over its body and black markings under its eyes. Its yellow eyes scanned its surroundings as it flicked its tongue to taste the air.

As it did this, a boy with unkempt curly green hair, and green eyes walked in front of the snake's path. Causing the small reptile to rear up and hiss at him defensively, getting the boy's attention.

"Huh? What kind of snake are you?" He wondered curiously as he knelt down to examine it. The snake hissed again as it flashed its fangs at him. "Hey easy! I'm not gonna hurt you, little guy, I just don't want you to get hurt. It's not safe out here." He told the little creature as he tried to reach its hand out towards it before...

CHOMP!

The boy screamed at the top of his lungs in pain as the snake bit him, causing him to jerk back as the venom coursed through his veins. The snake quickly darted off into the brush.

"Ahhhh! Oh! It hurts!" The boy yelled as he writhed around on the ground in pain. Meanwhile back with the snake, it continued to slither away, but curiously. Its fangs seemed to no longer have a drop of venom in them.

As the boy's arm slowly stopped hurting from the initial bite, he then started to feel light headed and dizzy as he tried to get up and walk.

"Have to… get… help…" He groaned as he finally got up only to fall again as he tried to walk. He then fell unconscious as the venom continued through his body.

(Later)

The boy slowly opened his eyes and he soon noticed that he was in his room on his bed, and that the sun was starting to rise. He sat up slowly before grabbing his forehead, feeling a throbbing migraine barrage his brain.

"Ugh… What happened…?" He groaned as he slowly sat up. The green haired lad tried to shakily get out of his bed and into his bathroom to splash his face with some cold water, but as he dried his face off and looked in the mirror… Shock enveloped him as he saw how different the face staring back at him was.

His face was pale almost white in fact, and it wasn't from fear. He also had green markings that went from underneath his eyes to the bridge of his nose where his eyes met. Speaking of which, his eyes were still green, but his irises and pupils were now like those of a snake. Lastly he also seemed to have developed fangs.

"What… What's going on? What's happened to me?" He gasped in shock as he continued to examine himself.

"Izuku! Are you alright honey?! Please answer me baby!" A woman's voice called from down stairs.

"I-I don't even know if I'm actually fine, mom! I've got the features of a snake!" Izuku exclaimed in reply. Quickly, he ran down stairs and found his mother in the kitchen, and when she turned to face him, she too was shocked at how much he had changed.

Minus his hair still being unkempt and green but how pale he was and all the other features were now radically different. She didn't know what to make of it.

"H-honey? What's happened to you?" She breathed with wide eyes.

"I—I don't know mom." He told her. "How did I get here anyway? All I remember is passing out after… That snake… Bit… Me…" He said slowly.

"A snake?" His mother asked in confusion.

"Yeah it was a little white snake. I was trying to move it so it wouldn't get run over or hurt, but it got scared and bit me." He told her. "Then I suddenly felt faint and passed out."

He was immediately bopped on the head. "Young man, you should know better than to go near snakes! You never know when it's a poisonous one!" She scolded.

"Sorry mom." Izuku winced as his migraine throbbed in response to the impact on his head. "But how did I get here? And can I get some medicine? I have a headache." He groaned.

"Oh! Right, sorry." The woman apologized as she got him some medicine. "And it was Mitsuki who brought you home when she found you lying on the ground on her way home. Honestly, it scared us both half to death Izuku!" She scolded, her cheeks puffed out.

This was Inko Midoriya, Izuku's mother. She was a woman in her mid thirties with a plus sized build, making her very curvy, but nonetheless beautiful to those who preferred big girls.

"I didn't even know it was a poisonous snake." Izuku pouted as he took the pills and drank some water to down them.

"Well, at least we know now that it didn't cause any damage. Honestly when the doctors checked you they didn't see anything wrong, just that it seemed to cause you to fall unconscious." Inko shrugged. "Now hurry and eat up, it's almost time for school." She told him.

"Right. Thanks, mom." The boy told her before he started eating. After getting his breakfast, he started heading to school, but soon found that his way was blocked by a sudden villain attack.

The heroes on the scene were Dead Arm, Back Draft, and Kamui Woods. The appearance of said heroes made Izuku smile as his inner fanboy came out.

"Kamui Woods! He might be new, but he's making an impression!" He said as he got his notebook out.

"From that dopey look on your face I can tell what you are." A man next to him said. "A fanboy!" He added causing Izuku to chuckle nervously.

Back with the heroes, Kamui Woods was busy fighting the villain. "Get away from me now or I'll break you, toothpick!" The giant man yelled as he tried to swat Kamui.

The man of wood deftly dodged and swung around before landing on a rooftop. "Robbery, resisting arrest, illegal use of powers during rush hour, and assault. You are the incarnation of evil." The hero growled as his wooden arm started to take shape. "Preemptive Binding…" He started to say.

"Here it comes!" Izuku grinned.

"Lackard Chain Prison!" The arbor hero yelled. Right as the attack surged forward, however…

"INCOMING!" A female voice yelled before the foot of a giant woman suddenly planted itself in the villain's face.

Said woman landed on her feet and grabbed the giant man by the collar. "Hi everyone, I'm Mt. lady. And you don't have to worry about this bum anymore." She smiled with a wink. The men in the area started talking pictures of her almost immediately.

Later on after everything was settled, Izuku started taking notes about Mt. Lady while mumbling to himself. "I wonder, could that snake bite have given me any powers? I feel different than I was yesterday…" He wondered to himself before his arm suddenly turned into a snake. "What the-!" He squawked in surprise. After shaking off his surprise, he looked at it and saw that it looked like the snake that bit him.

"Whoa…" He gasped as it turned back to normal. "... I wonder what else I can do?" He wondered as he walked to class.

As he approached his school though, he constantly noticed that people were looking at him and staring.

"It's my new look, isn't it?" He deadpanned. Honestly, what else could it be?

"Hey, Bakugo look." A boy said as he elbowed the Pomeranian blonde next to him. "What the heck do you think happened to Midoriya?" He asked.

"Not sure. Oi, Deku! Do you think since makeup and contacts will make us think you have a quirk?" He taunted, getting some laughs from the other students.

Izuku turned towards him and glared. "This isn't fake, Kacchan. I got this way after I was bitten by a snake yesterday." He snapped, his tongue (which was now elongated) flicking out of his mouth every time he made the 's' sound. The sight of his tongue made his old friend pause.

"... Did anyone else see his tongue?" He asked as he looked around.

"We did." The other two nodded. Izuku, now confused, just continued walking and examined his tongue on the way to class, soon finding that like his arm he could turn it into a snake.

'This is just getting weirder, even by today's standards.' He thought as he sat at his desk. As he sat there he kept contemplating the many ways he could use his new abilities, when his teacher began speaking.

"Now, since you'll be going into high school, it's time that you start seriously thinking about what to do with your lives!" The man said. "Now I could pass out career aptitude tests… But why bother?" He asked as he tossed them in the air. "I know you all want to join the hero track!" He exclaimed. Right on cue, everyone just started using their quirks while cheering. Izuku just shut it all out.

"Yes yes you all have amazing quirks, but now power use in school!" The man said.

"Hey teach!" Bakugo called. "Don't lump me in with these guys, I'm the real deal but they might only get a job as sidekicks to some busted D-lister. Ha!" He laughed.

"You think you're better than the rest of us, Katsuki?!" A male student yelled.

"Ah yes, Katsuki, you're thinking of joining UA, right?" The teacher asked as the other students gasped.

"Yep. I'll be even more popular then All Might himself! And be the richest hero of all time!" The boy nodded as he jumped on his desk. "And it all starts with UA high!"

"Midoriya, don't you want to get into UA too?" The teacher asked, killing the Pomeranian's groove.

Izuku seemed to stiffen as his new tongue flicked. "Um… Yes?" He said nervously, his 's' sounds being elongated. This caused everyone to stare at him.

"You actually think you can get into UA?!" Katsuki barked in irritation. The boy was about to send an explosion on Izuku's desk when out of reflex, the green haired boy's arm shot out what looked like a boa constrictor out from inside his sleeve and it wrapped around Bakugo's neck. "WHAT THE FU—ck?! He got out in surprise before his air pipe was cut off.

Izuku, realizing what was going on, quickly retracted the Serpent and got up. "I'm sorry, Kacchan! It was an accident, I didn't mean to!" He told the boy on the floor.

"When in the world did Midoriya learn to do that?!" A girl asked in shock.

"Okay that's freaky as hell." Another male student said.

Izuku backed up as Bakugo glared at him. "I'm sorry." The boy told him softly.

(Later)

The green haired boy sighed as he got his things packed. Luckily, his teacher didn't give him any trouble since he wasn't used to his powers and it was in self defense, but it was still a close call.

He was about to put away his hero notebook, when Bakugo grabbed it.

"What do we have here?" The exploder 'wondered' as he held it. "A hero notebook? What are you doing, taking notes on how to be a hero?" He questioned.

"Give it back, Kacchan." Izuku told him. He was responded to by having it thrown in his face. Then the blonde placed a snake encyclopedia on his desk.

"Show me what snake bit you. I want to get to the bottom of this." The boy ordered. Izuku, feeling curious about it himself, did so. After flipping through several pages, he found an image of the snake that bit him.

"This one." He said, pointing to the picture under the 'mythical' section.

"The Shiro Orochi, you're positive?" The exploder boy asked in clear disbelief.

"I am. There's no way I'd forget a snake like this." Izuku nodded. Bakugo took a closer look at the book.

"That's impossible. It doesn't even exist." He said. "This snake is said to roam the mortal world gathering up venom in its fangs so that it can pass on its power to whoever it bites."

"Okay… Does this happen often?" Izuku asked.

Bakugo looked at him as if he were an idiot. "No, ya damn nerd! It can only get enough venom for one bite every thousand years!" He yelled. Izuku processed that information and looked at his hands.

"I guess I'm the one it passed the venom on to." He muttered. "How else would I look like this all of a sudden?" He mused.

"Maybe." The blonde shrugged before jabbing his finger into the boy's chest. "But don't think this changes anything, Deku. You're still not better than me, so don't you dare get in my way!"

Izuku gulped nervously and nodded. "Y-yeah, sure." He nodded as the boy left.

(Later)

Later on, the boy was under a bridge trying to figure out what all he could do. So far he could transform any body part into a snake or like that of a snake. Unhinge his jaw, elongate his tongue, sense heat, shoot snakes from his mouth and arms, and apparently was now able to stretch his limbs, was stronger, faster and more agile than before, and was now cold blooded. There was still a lot more to find out, but these things were definitely a starting point.

"How many snake based abilities do I have, waiting to be discovered?" He wondered, not seeing sludge start rising up from the sewer cover he walked past.

Soon the sludge covered him and started trying to grab him. "This must be my lucky day, you'll be the perfect skin suit for me to use to skip town! Thanks kid, you're a real hero!" The sludge said as eyes appeared on it.

'Shit! Gotta get away!' He thought before he suddenly felt something rise in his throat. When he opened his mouth… He shot himself out and landed on his feet. He was free of the sludge man and, thankfully, still had his clothes and belongings on his person. "... Um… Huh?" He uttered in confusion. He just shredded his skin like an actual snake!

The villain looked at the boy and then the lifeless shed skin in his grasp. "What the hell are you?" He asked right as the manhole cover behind them popped into the air.

"There's no need to fear…" A deep voice began, drawing the attention of the two. The sludge man's eyes widened in fear.

'No… Not now!' He thought.

"Now that I am here, that is." The man behind them said as he towered over them both.

"No way…" Izuku gasped in shock.

"Texas Smash!" He yelled as he threw his fist forward, sending a shockwave at the sludge man.

'Can't...hold...together…!' He thought before he was blown apart. Izuku meanwhile was having a hard time standing and ended up falling on his ass due to the force.

'He's here… I don't believe it.' He thought in disbelief and excitement. All Might quickly gathered up the villain inside a bottle and walked over to the boy.

"Are you alright, young man? That was quite a scary encounter you had there." He asked, helping him up.

"He caught me for a moment, but I managed to snake my way out." The boy replied. The muscular Hero was about to say something about his features when he was beaten to it. "Yes, I know that was a pun." He said.

"Ha ha! Mind if I get your name, young man?" He asked. Izuku nodded in return.

"Izuku, Izuku Midoriya." The boy replied. "Umm…" He hummed as he pulled out his notebook. "Don't suppose you could sign my notebook?" He asked.

"Sure." He replied before doing exactly that. "Well, I better get a move on. It was nice meeting you, young Midoriya!" All Might said as he readied himself to jump.

"Wait! I was hoping to ask you something!" The boy said as the man leapt away. "Well here goes nothing…" He said as he shot a Serpent from his arm and wrapped it around All Might's leg, taking him with him.

"What the-" The man uttered, feeling something wrap around him. Looking back, he was understandably surprised to see a serpent with Izuku attached to it. "Are you serious?!" He asked in disbelief.

"Sorry but I really need to ask you something!" The boy yelled.

"Let go! I love my fans, but this is too much!" All Might said as he tried to unwrap the Serpent around his foot.

"I can't let go now! If I do that, I'll die!" The teen yelled.

"Oh! That's a good point." The man said as he ceased his efforts in removing the Serpent. The hero quickly landed on a nearby building and the snake boy tumbled to the ground.

"Ohhh, I just saw my life flash before my eyes…" He sighed. However he quickly shook his head and looked at All Might. "I'm sorry about that but may I please ask you a question?" He asked as steam seemed to come off of the Symbol of Peace. "All Might, do you think I can be a hero, even if I wasn't born with the powers that I have?" He asked as a large cloud of smoke surrounded the hero.

'Oh no… Not now!' He thought in alarm before his whole body was consumed by the smoke. Izuku seemed to regard the scene with confusion before he saw it clear, and standing in All Might's place was a skin and bones man with floppy blonde hair.

"WHAT THE HELL?!" The green haired boy yelled in shock as he, in his surprise, accidentally completely unhinged his jaw, causing it to drop to the ground.

"Uh… Are you gonna pick that up?" The man asked awkwardly as he pointed at the jaw.

Izuku quickly recomposes himself and brings his jaw back up. "But… I don't understand, what happened to you?!" He asked in confusion.

"Well, you know how those guys at the pool swell up to look buff? I'm like that." The lanky man stated. "As for why…" He trailed off as he lifted up his shirt, and caused Izuku to grimace at the sight of a very nasty looking wound. "This is my reason." He revealed.

"No way…" The boy gasped.

"Yep. Happened five years ago. Took nearly half of my respiratory system and ripped a huge hole in my stomach. The surgeries I had gotten kept the damage from getting worse, but there's not much else that can be done." The man explained. "It hurts when I eat, breathe and try to move. Hence why I'm only able to be All Might for only three hours a day."

"Five years… Was it the fight with Toxic Chainsaw?" The boy inquired.

"Good eye, but no. This one I kept under wraps." The blonde explained. "Now, what were you saying about you not being born with your powers?"

"Oh, right." Izuku said before clearing his throat. "My powers are the result of a snake biting me and injecting me with venom. This took place yesterday." He explained.

"Yesterday…?" The lanky man muttered in confusion. "What kind of snake bit you, exactly?" He asked.

"According to what I've learned, it was the mythical Shiro Orochi." The serpentine boy replied, causing the Hero to freeze and look at him with wide eyes.

"You're certain? That snake was thought to be just a myth from the feudal era." All Might asked, seeming a bit skeptical.

"I'm certain. There is no other way for me to explain the features and abilities I now have." Izuku replied seriously.

All Might took this in and began thinking. "I'm unsure if you'd be able to do well as a hero with powers you're just now discovering. But, I could be wrong." He said.

"Yeah, I've got work to do and data to gather on my abilities." The boy sighed tiredly. "This is gonna be a chore." He muttered.

"Well, best of luck then." The man told him as he left.

(Later)

Later on Izuku was beginning to make his way home while jotting down the abilities and applications of said abilities he now knew of and had. There was still room for addition though, of course.

"I can turn parts of my body into snakes of various kinds, and according to what I heard earlier today, I've got a snake tongue and an unhingable jaw now… And all of this from one snake bite from a mythical Serpent." He muttered. He then sighed. 'One day is all it took for my life to turn around.' He thought.

However before he could think of more things to jot down, an explosion occurred off in the distance from where he was.

"What was that?" He wondered before making his way to the source. But when he found it, he saw the same sludge villain from before, and his snake eyes could pick up the thermal image of a very familiar looking blonde in its grasp. 'He's got Kacchan!' He thought in alarm.

The heroes nearby were having unholy hell trying to wrangle the villain up and keep everyone safe, and the situation was only compounded by the immense amount of property damage and fires Bakugo was causing as he tried to get free.

Izuku looked on in guilt and horror, realizing it was probably him who caused this. But before he could dwell on this fact, his instincts compelled him to start running towards the battle.

The boy suddenly transformed his bottom half into that of a snake's and weaved through the crowd before changing back and then out of instinct, opened his mouth and sprayed a green fluid into the villain's eyes.

"AAAAAAGGGGHHH! MY EYES!" He screamed in agony, his grip on Bakugo slacking and allowing the boy to escape.

"Did you spit something into his eyes?!" He asked incredulously as soon as he was clear.

"Yeah, it was some sort of venom I think." Izuku nodded. The villain glared at him as his fist became huge.

"I'LL CRUSH YOU, YOU LITTLE CREEP!" He yelled as he slammed his fist down, only for the boy to dodge.

Izuku started spinning in mid air as his body started to change and elongate until he was the size of a large culvert pipe and coiled up like a rope. His now serpentine body covered in rough white scales as he rose as a large white snake, green markings under his green eyes.

"What the…" Death Arms muttered in shock as he and Kamui looked at the boy in shock and surprise. Mt. Lady was shocked as well along with the crowd.

The large Serpent rose up until he stood taller than the villain and flicked its tongue before it hissed and flashed its fangs in a threatening display. Its tail was rattling as it swayed from side to side in an almost hypnotic manner.

"You think just because you're a giant snake that you can beat me?! In your dreams, brat!" The sludge man exclaimed as he threw a punch, only for his target to evade it with no effort.

Izuku hissed threateningly again as he did a mock strike, making the villain back up. He attempted this several more times before one of his strikes caused him to bite the man in the eye.

"MY EYE!" He screamed in pain. He was about to strike the boy turned snake again but was blocked by someone else. It was All Might! He had seen the whole thing and was motivated to help due to Izuku's bravery.

"I really am pathetic, aren't I?" He said to himself. "I'm sorry young man. I told you that with your inexperience with how your powers work, that it would be astronomically difficult for you to be a hero. But clearly, I was not living up to what I preached!" He exclaimed as he glared at the villain present. "Pro heroes are always risking their lives! That's the true test of being a hero!" He continued as blood gushed from his mouth.

Izuku quickly rushed over to and coiled around Katsuki, sensing what was about to happen. All Might then brought his fist back and then charged up his power.

"DETROIT! SMASH!" He yelled as he delivered a massive haymaker to the sludge villain's face. In an instant, the villain was blown apart and a tornado was created. Mt. Lady shielded the crowd behind her arms as the wind blew against them all.

When it dissipated, rain started to fall down on the streets, causing the fires to be quickly put out while also making some people in the vicinity wet. Meanwhile, Izuku uncoiled himself and let Bakugo free.

"Hey, it's raining." Someone noted.

"Wow! All Might changed the weather with one punch!" Another added.

"He really is the greatest hero ever!" A third added. All Might was then swarmed by the press as Izuku turned back to normal, and the heroes briefly accidentally mistaking him for another villain due to his appearance.

"Villain! Get him!" Kamui exclaimed before Bakugo got in the way.

"Whoa! Easy idiots! He's not a villain! He's the one that got me out of that situation!" He told them.

This made them take a better look at him and realize that it was indeed him. "Oh. Sorry, our mistake." The heroes apologized.

Izuku sighed in relief as he fell on the ground. This was exhausting.

(Later)

After that whole fiasco, Izuku was finally headed home, but not before Bakugo stopped him. "Listen, Deku, I don't care if you have powers now or not. You're still a weakling who can't fight worth a shit to save his life! So don't you forget it! I don't owe you a damn thing for helping me!" He yelled as he stomped away angrily.

'... What was that?' The green haired boy wondered before shaking his head and continued on his way. 'Whatever. I still have data to record.' He added in his thoughts.

"Ha ha! I am here!" All Might said as he suddenly appeared out of nowhere.

"AAAAHHHHHH! WHAT ARE YOU DOING HERE?!" Izuku yelled in surprise as he tried to calm his heart.

"Why I stand for justice, not soundbites! I come to anyone who is in need!" The man said as he flexed. "Because I am—!" He started to say before he deflated and sprayout some blood. This caused the snake boy to let out another startled scream.

The blonde coughed as he wiped his mouth. "Young Midoriya, I came to talk to you about our conversation from earlier." He told the boy.

"What about it?" The boy asked with a raised eyebrow.

"While I was correct that your situation would make it very difficult to be a hero. You proved to me back there that those assumptions are not as iron clad as I thought." The man told him. "After all, even though you had no idea how your powers worked, you still tried to save that kid. Moving on your own without thinking, like a true hero."

"You're serious?" The teen asked with wide eyes.

"Yes. Young man, it is my belief that you can become a hero." He declared. This caused Izuku to start tearing up. This was something he really wanted to hear, and he was hearing it from someone he considered to be his idol!

"I deem you worthy of my power. My quirk is yours to inherit." The symbol of peace said with his arms outstretched. This statement caught the boy off guard and caused him to become confused.

"Wait, huh?" Izuku asked in complete and utter confusion. Inherit? What did he mean by that, he wondered?

Dragon Emperor0: And there it is guys, our newest story. An AU where Izuku gains the powers of Orochimaru from Naruto.

ThermalsniperN7: Yep. He's gonna scare a few people here and there because, well, why not? It's gonna happen at times.

Dragon Emperor0: Yeah. Anyway guys, see you next time