GR noted that mach 20 is nothing in Tsuna's eyes. Which, I belatedly realized, was completely true. And therefore, Tsuna would have no problem killing Koro-sensei. So the reason was changed into the scientists of Vongola wanting to study Koro-sensei and needing first hand information so Chiyo was sent. I already edited it in the previous chapter. Thank you so much to GR who pointed this out!


Koro-sensei was a mystery in every form possible. That much was certain. In the few days she had observed him, she was stumped. When she had first received this mission, she had expected, well, a monster.

The octopus before her definitely wasn't it.

She watched as the being in question hoarded the leftover candy from the experiment. A wry small fought its way to her lips and she let out a huff. If anything, Koro-sensei was more child than monster.

A child living in a monster's body, she snickered. Now that's a bestseller. Shaking her head lightly to pull herself out of her thoughts, she helped her group in returning the many beakers and liquids where they belonged.

"Um...Sensei."

The quiet voice had Chiyo turning her eyes back to the front of the classroom where a short girl wearing glasses nervously held a few vials filled with unidentifiable liquid. Chiyo cocked her head to the side as the girl thrust the vials towards their teacher.

"These contain poison! Please drink them!"

Chiyo blinked before chuckling. Well, that was terribly straightforward. The rest of the class agreed with her sentiments as they sweatdropped.

"Ah, er, I-I'm not good at surprise attacks like everyone else...but chemistry is my strong point so I put my all into making these!"

Curiously, Chiyo set her eyes on the teacher. She doubted he would drink it. After all, although Okuda was merely a middle school student, she may still be able to concoct something that could kill the monster.

"My goodness. Well then, down the hatch," Koro-sensei cheerfully stated as he downed one of the vials.

...What.

Her brown eyes narrowed once more. Koro-sensei started to shake a bit. Chiyo leaned a little forward, anticipating the results. She did not blink once, wondering just how Okuda's poison would affect the octopus.

She blanked when some weird looking horns popped up in the back of his head. With the heel of her palm, Chiyo massaged her forehead. Of course it wouldn't be easy. Having her expectations completely destroyed with just that one vial, she watched with crossed arms as he drank the remaining two vials.

The second vial merely gave him wings on the back of his head and Chiyo had to wonder just what his makeup was for him to have such needless reactions to different chemicals. It was more absurd than Reborn's costumes and that was saying something.

The last vial, despite its long buildup, merely yielded a straight face from Koro-sensei. By which she meant, a clearly straight face. The ever present grin that usually adorned their teacher's face was now gone. It was a feat in and of itself because Chiyo could not recall a single moment in which his grin had faltered.

"Your expression is so tiny, Sensei!"

"It looks like an emoticon!"

Koro-sensei looked at them blankly. "Even if you hate me, please don't come to hate assassinations."

"What's with that, all of a sudden?!"

Sometimes Chiyo wondered if she was being taught by a living gag or the monster that had destroyed 70% of the moon. To be perfectly honest, Chiyo was beginning to doubt that Koro-sensei had even destroyed the moon and was just taking the credit of some other being. It seemed far more plausible.

Her faith in him dwindled even more when he offered to research a poison that could kill him after school with Okuda.

There is no way he takes any of this seriously, Chiyo thought idly. If it weren't for that incident with Karma, she would believe that Koro-sensei was just playing with the group of students and the government.

But he seriously cared for his students and their growth. That was the one thing she couldn't quite wrap her head around. It was a little baffling, really. What was his drive and motivation for all of this?

Sighing, she decided to voice one of her other questions. "Speaking of, Koro-sensei, could I cut off a part of your tentacle to examine? I might find something interesting."

Koro-sensei had been very supportive of everyone's assassination attempts and he seemed to be rather eager to help them try. Thus, she had decided to just bite the bullet and ask for some of whatever made his being.

"Nurufufufu," Koro-sensei laughed. "Sure! Please do use it wisely."

Chiyo gave a small shrug of her shoulders as she grabbed an unused vial and threw it to Koro-sensei. The octopus took an anti-sensei knife using a handkerchief and cut off a bit of his tentacles and let it slide into the vial.

"Are you interested in chemistry too, Chiyo-san?" he questioned as he passed the vial back to her.

The girl shook her head. "Not particularly. But I do know a few things."

She held the vial full of yellow antimatter and brought it up to her eyes. A smile curved on her lips. Shoichi and the others would be happy to receive this.


"Wrong answer," Reborn commented as he pushed down on the button of one of the remotes.

The explosion threw her back and a few burns littered her exposed skin. She whimpered at the pain as water pricked her eyes. She sent a wronged look towards the man languidly lying on her bed who stared back at her innocently.

"This is child abuse," she complained. "I'm pretty sure I can get you arrested for this."

Reborn snorted and his hand moved to the next remote. "Why don't you give it a try, BakaChi?"

"Okay! Okay! I'm sorry!" Chiyo exclaimed. "Don't press that button! I didn't even get that question wrong yet."

"Yet?" he echoed. "Well, if you're planning on getting that question wrong then I'm sure no harm will come from pressing this a little early."

Chiyo let out a strangled sound of frustration as she fell on her back. "Fine. Just blow me up. Death is better than continuing with you."

Reborn's lips tugged downwards the slightest bit, too small of a change for anyone to notice. His onyx eyes watched her assessingly.

The lack of a response had Chiyo sitting back up and looking towards the man. She let out a disgruntled, "What?"

"When are you planning on sending the vial to Italy?" Reborn finally questioned.

Chiyo glanced over at the vial of yellow that she had precariously thrown on her desk. The sight made her sigh out loud. "Probably with the report tomorrow." The reminder of the report had her nose scrunching up.

She should probably get started on that soon. Her brother truly was torturing her by having her compile weekly reports. He was probably just trying to get back at her for all the times she had mercilessly teased him or helped the others in increasing his own paperwork. It was times like this she wished her clumsy older brother was back instead of the monster who made her work.

"We'll finish up here for today," Reborn cut through her thoughts.

The words had her eyeing him suspiciously.

His face contorted into a scheming smirk. "I'll be waking you up bright and early tomorrow."

With a lazy wave of his hand, Reborn left her room, leaving Chiyo to mentally cry. She wanted to go back home. How the hell did her brother deal with that spartan for so long? Chiyo had definitely been at the mercy of Reborn before but it was sparse and there were long breaks in between. This daily interaction had her previous worship of the hitman dwindling into fear.

Wincing at the wounds from the explosions, she stood up. She groaned at her now ruined clothes before moving through her nightly routine. Once dressed in her pjs and ready for bed, she picked up the vial that she had thrown aside recklessly and opened the drawer by her bed.

Chiyo placed the vial inside and was about to close it before she caught sight of a small box in the corner. With eyes a little lost, she picked up the box and flicked it open. One finger mindlessly rubbed the orange stone in the middle. A strip of silver wrapped around the orange stone with the Vongola crest inscribed in it.

She slipped the ring onto her index finger. Energy thrummed under her skin, finding some harmony with the ring. Taking a deep breath, she took off the ring, put it back in the box, and put the box in the spot she had picked it from. Breathing out, she closed the drawer.


At the very least, Reborn had healed the obvious wounds that had littered her body. He left the others with the simple explanation of "increasing pain tolerance". Chiyo called bullshit. He just wanted her to suffer a little more.

Finding herself back in the classroom, Chiyo once again questioned the state of their homeroom teacher's mind as she listened in on Okuda's conversation with Nagisa and Kayano.

"..so then, he told you to go make that toxin?"

"Yes! And that, theoretically, this should give the best results," Okuda responded with a grin.

Chiyo wondered if their target's words should be trusted.

"He even put the proper storage methods for poison in this manga," Nagisa pointed out as he flicked through the manga. "Koro-sensei's just as courteous as always."

"He's been supporting me all along. He said that even if I'm bad in Japanese, I should embrace my strong points."

There it is again, Chiyo mused, that unadulterated support and encouragement. What was he thinking? She just wanted to crack the teacher's head open so she understood what exactly was going on. She would need more information than what was currently available to her. If she wasn't mistaken, Nagisa was keeping a list of notes on Koro-sensei's weaknesses.

When Koro-sensei entered and drank the supposed poison, Chiyo's thoughts were confirmed. The target was, without a doubt, the most familiar with his own body. It would not be a stretch to say that Koro-sensei knew exactly what chemicals could supposedly harm or kill him. Therefore, it would be more than a little stupid for him to help Okuda with creating a poison to kill him.

No, there was definitely another reason.

Soon enough, Koro-sensei was a pile of goo and explained that the 'poison' was truly just a formula to increase his fluidity. With his newfound powers, he would be able to slip into smaller crevices and spots, making it even harder to kill him. Mentally, Chiyo noted to add this new development into her report before she sent it off.

"You tricked me, Koro-sensei!" Okuda accused and Chiyo honestly wondered why the girl was so surprised. Despite his rather childish personality, Koro-sensei did claim to have destroyed the moon.

However, his next words jarred her.

"Okuda-san, in assassinations, deceiving people with your language is also a necessity. No matter how excellent the poison you've created...if you hand it over with naive honesty, then just like this time, your target will take advantage of you and that will be the end of it." The pile of goop looked towards Nagisa. "Nagisa-kun, if you were to give me poison, how would you do it?"

Nagisa mulled over the question for a moment before answering. "Hmm, I'd break the poison up into a sweet juice that you'd like and give that to you, saying it's specially hand-made. Something like that, I guess."

"That's right," Koro-sensei agreed as he slipped back down to the ground. "To deceive someone, you must know your opponent. You must plan out your words. The power of language is a necessity to skillfully deliver poison." He returned back to his original form. "Your talent in science can be useful to everyone in the future. In order to make that understandable to many people, please also work on the power of language and its role in delivering poison."

The reason he went through all of that trouble in 'helping' Okuda...was to teach her a lesson…? She pressed her lips in a thin line as the octopus retreated back to his usual goofy self. What does he want? Who is he?

Her eyes slid from Koro-sensei and towards Okuda. She jumped out of her seat and headed towards the girl. "Okuda-san."

Snapping out of her reverie, Okuda looked at the brunet. "Yes?"

"The formula of the poison you gave to Koro-sensei today, can I borrow it?" Chiyo asked with a smile.

"Ah, sure," Okuda said as she rifled through her bag and brought out a piece of paper and handed it over to her.

Chiyo's eyes flicked through the chemical formulas. She didn't understand any of it. Grinning at the girl before her, she said, "Thank you~! I'll return it to you later."

"You know, Chiyo-san," Karma began, popping up besides her. "I haven't seen you try assassinating Koro-sensei once. Do you have some grand plan set up?"

She lightly chuckled, shaking her head. "Not at all. I haven't really come up with a feasible plan yet." What was the point in even trying to kill the octopus? She'll leave that to people who had the ability to do so. "Oh, Nagisa-kun, can I see the list of weaknesses you have for Koro-sensei? Maybe I'll be inspired then."

Nagisa grabbed the notebook from his pocket and handed it over. "Sure. I only just started it so there's not much to it."

Chiyo quickly flicked through the few short notes.

1. When he tries to act cool, his weaknesses show

2. He is surprisingly quick to panic

3. No tolerance

4. His punches are weak.

After committing them to memory, she smiled at the androgynous boy before hopping back to her seat. Karma watched her retreating back with a curious gaze.

"Don't you think she's a little interesting?" he asked Nagisa.

Nagisa joined Karma in looking at the brunette. "I guess. She's a little apathetic to everything."

"She doesn't like me for some reason," Kayano jumped into their conversation with puffed cheeks.

The two boys turned towards her. "What do you mean?"

"She tenses everytime I get close and she always cuts our conversations short," Kayano explained, a little indignant. "I didn't even do anything to her. She gets along with everyone else just fine!"

"She probably found out some shameful secret you hid," Karma teased causing Kayano to blush.

"I don't have any shameful secrets!"

Karma didn't get the chance to retort because the bell rang in a timely manner. Instead he shrugged and remarked, "Who knows~?" before strolling back to his seat.


It was after school that Chiyo brought up the topic of Kayano Kaede with Reborn. Admittedly, she should have done so before but Reborn always seemed to know everything and she was extremely sure he would've already assessed her level of threat by now. And if he hadn't said anything, Kayano was, perhaps, not that great of a deal.

But the girl was slowly beginning to be a problem because she just felt so wrong and being in the same classroom as her day after day was just too much.

"Her flames are in discord," Chiyo said, her eyes on her feet. "I've never felt anything like that since that one guy Tsuna-nii went up against a few years ago."

"I know," Reborn dryly answered.

"And her name's not even Kayano Kaede. Is she a secret assassin or something? Someone else sent to deal with Koro-sensei?"

Reborn gave a shake of his head. "A background check revealed that she has no affiliation with the underground."

"Then who is she? What does she want? What's her real name?" Chiyo interrogated, looking at Reborn with inquisitive eyes.

"Find that out yourself BakaChi. If anything, I'm more interested in her relationship with the octopus." Reborn's eyes narrowed.

Her eyes widened. "What?! Are you implying she knows Koro-sensei? Like, before he began teaching?"

Danger dinged in the back of her head and then there was the sound of a gunshot. In the next moment, she was hissing in pain. Blood leaked from the grazed skin of her shoulder. Scowling at the hitman who held a smoking gun, she applied pressure to the newly created wound.

"Can we go one conversation without you shooting or hitting me?" she complained but there was more resignation in her voice than bite.

"You should learn to read the expressions and body language of everyone," Reborn criticized. "More importantly, you need to be able to read any possible threats. The mist may be a good actress but she still lacks quite a bit of experience."

Chiyo pursed her lips, the logical side of her understanding her faults but her heart rejecting them. "Ugh. Okay. What does that have to do with her knowing Koro-sensei?"

Another bullet grazed her. This time her other shoulder and she swore. "What the hell Reborn?"

She shut up when she noticed the thinly veiled irritation swelling in the hitman's eyes. Carefully, she went through their conversation up until this point and connected the dots on her own. She kissed her teeth before trying to appease the irate man.

"Okay, okay. So, Kayano shows hints of knowing Koro-sensei but Koro-sensei's supposed to be an alien who blew up the moon so how could she know him?"

Reborn looked at her as though he was looking at the biggest idiot alive. Chiyo dwindled under his gaze which was beginning to grow abnormally bloodthirsty. She had disappointed him. Her left hand clutched her right arm as she dug her nails into skin. She removed her eyes from his face as the aura around him increased and placed pressure on her.

"You didn't check his flames," Reborn said flatly.

Chiyo stilled. "He has flames. But, but, he's not human."

"Neither is Kawahira."

She opened her mouth to refute but had no words to that. Chiyo ran a hand through her hair in frustration. "Well, how was I supposed to know? The guy certainly doesn't look human so I assumed-"

"20 laps around the neighbourhood," Reborn interrupted. At her gaping mouth, he added, "Now."

Tugging down his fedora, he watched as she ran straight out of the house. He got up and moved to follow her, albeit at a much slower pace. Sawada Chiyohime reminded him too much of his ex-student, now the Vongola Decimo or Neo Primo.

But she shouldn't.

The girl had practically grown up with the mafia. She had been exposed to danger since she was a child and should, therefore, be more than capable in identifying and assessing threats on her own.

It seemed as though she was too spoiled by her brother.

"Dame-Tsuna," the hitman gritted out through clenched teeth.

No wonder Tsuna had suddenly assigned him to be Chiyo's tutor. Having gone through his torture, Tsuna never wished the same experiences on anyone, let alone his own baby sister. However, it seemed as though the Decimo noticed a few peculiarities about the girl.

Sawada Chiyohime, no matter how much Tsuna hated it, was now a part of the mafia. If she did not learn to grow up, and do it quick, she would be found gutted in some random ditch. And Tsuna knew, he knew all too well, that despite Reborn's violent methods, he would be his best bet.

"Throwing a mess you made onto me."

But he wasn't the World's Greatest Hitman for nothing.


He was a Rain.

Koro-sensei, in all his octopus glory, had flames.

What.

She had checked as soon as she could. Her check led to the teacher jumping and crying "Ghost!" but she could not focus on his high pitched shriek that put even her brother's to shame. Instead, she sat back in disbelief as she kept her eyes on the panicking octopus.

He was a Rain.

That newfound revelation left her reeling because how could that monster have flames? Not even animals did! So how could he? True, Kawahira may not have been human, but he held a connection to the Tri-Ni-Sette and therefore, him having flames was not that big of a deal. But for the yellow inhuman octopus to have them?

Unless he was human.

Looking back at his three feet of yellow and tentacles and bulbous head, she decided no. This thing could not possibly, ever, be human.

So, days passed, and Chiyo slowly came to accept the fact that Koro-sensei truly did have flames. And to express her disgruntlement about the fact, she continuously brushed her flames against his whenever he was relaxed.

(He ended up thinking he was haunted and went to an exorcist. When she heard, she stopped which only scared the octopus even more for it indicated that he was, truly, haunted.

.

.

.

No one believed him.)

And so, here they were, a month into the school year, eleven months before graduation, and facing an absolute foreign beauty. She checked all the boxes of normal hormone driven boy's dreams and she was clinging onto Koro-sensei with the brightest smile on her face..

"...Allow me to introduce the part-time foreign language teacher who has come today."

"My name is Irina Jelavic," she chirped. "Nice to meet you, everyone!"

Chiyo snorted softly, heard only by the two boys beside her. So fake.

"Oh?" Karma turned to her. "And why do you say that?"

Chiyo looked at him slowly. Had she said that aloud? She was about to fall back into her thoughts but the red head was still looking at her with curious eyes and his head tilted just slightly to the side.

Instead, she smiled and offered the simple explanation of, "Intuition."

Zoning back into the conversation going on at the front of the classroom, she heard that the foreign beauty would be taking over half of the English classes. She massaged her temples when she noticed the love stricken expression on the octopus's face as he stared a little unabashedly at the woman's breasts.

Despite not looking human, Koro-sensei was just as flawed as any other normal man. He was full of holes and weaknesses yet he was just as powerful. It truly made her revisit her theory on the monster possibly being human. After all, human experimentation was a thing. Besides, if magical flames exist, why not humans who've become octopuses? Or was it an octopus that was experimented on to become human? Or a weird experimentation where a group of scientists decided to meld a human and an octopus together and added in some extreme side benefits?

(Being perfectly honest, she wouldn't be surprised if someone experimented with octopuses. They were insanely smart. The prime example being Oodako.)

But that wasn't the point. The point was that Koro-sensei could be human. Which would be bad. Because what if there were others like him? Less nice and more than willing to blow up the Earth without warning?

Whatever. She was sure her brother already thought these things through and had them covered. Right now, her problem was the blonde foreigner at the front of the room trying to seduce Koro-sensei.

The moment the woman began to compliment Koro-sensei and comment that she was 'captivated' by him, the entire class knew it was an act. Which meant she had an agenda. And said agenda probably had to do with assassinating Koro-sensei because why else would a new teacher join their classroom?

But seduction? Really? Chiyo had to commend the woman's professionalism because how could anyone not blank at the sight of Koro-sensei and instead, fawn over him. That required a lot of mental strength. Especially when the victim isn't that appealing.

Like seriously, the dude's an octopus. And he's disgustingly yellow too.

Irina Jelavic, she rolled the name around in her head for a few moments. That was her true name and it was surprisingly familiar. That did not bode well because Chiyo did not know many names and the names that she did know often correlated with the mafia or the underground world. The woman could not have been too important if she couldn't immediately put her name to a title but she guessed she would have to check who she is with Reborn later on.


It was during their break that Irina showed her true colours. They were outside, trying to assassinate Koro-sensei (Chiyo lackadaisical in participating) while trying to get the soccer ball from him. Irina had quickly pulled out her charms and sent the octopus to Vietnam for some coffee.

"So, umm, Irina...sensei? Class is starting, so should we return to the classroom?" Isogai questioned with a little hesitance.

"Class?" She brought out a cigarette and lit it. "...Oh, right. You are all free to do as you see fit. Also, could you stop being so familiar with me and calling me by my first name?" The change in facades was smooth and Chiyo mentally applauded her. "I have no intention of playing the part of a teacher except for when I'm in front of that octopus. Call me Jelavic onee-sama."

The others watched her with wary eyes, more than a little disconcerted. The entire atmosphere was tense. Of course, a certain red head wouldn't take her words lying down.

"...So, what now, Bitch nee-san?"

"Don't shorten it!" the woman exclaimed, pointing at Karma.

He grinned at her, sharp and sly. "You're a professional killer, right? Will you really be able to take out that monster alone when the class can't kill him through their combined efforts?"

Her previous irritation gave way to a look of superiority. With languid coolness, she answered, "The difference between brats and grownups is how we adults do things." She turned towards Nagisa. "You're Nagisa Shiota, right?"

"Oh my," Chiyo murmured as the woman straight up french kissed the boy. "Do we report her for sexual harassment and pedophilia?"

"Come to the faculty office after this," Irina ordered Nagisa after she stopped her assault on the poor boy. "I want to hear the information you've gathered on that guy." Her eyes sharpened. "I have plenty of ways to make you talk." She turned towards the rest of the class. "As for the rest of you! Those with useful information come and speak with me-"

Chiyo scoffed. As if anyone would be willing to help her. That air of superiority does not go over well with this particular class.

"-I'm doing you all a favour. And I'll even lend some manpower to the girls." Three men walked over with practiced steps that indicated their training in martial arts. "A professional's job lies in having both skill and personal connections. You brats should sit quietly on the sidelines and watch." A gun was handed to her. "And, if you get in the way of my assassination mission even a little bit…" her tone darkened, "I'll kill you."

Chiyo tensed up. She wasn't joking.

Her eyes flicked over to the rest of the class and she did not have to be a master in reading facial expressions to understand what they were thinking. They did not like her. Those words that were spoken to belittle them- they were not having it.

They suffered enough at the hands of the main building and in some twist of fate, they found refuge in this shabby building at the top of a mountain.

The hitwoman was breaching their refuge.

And their killing intent flared in retaliation.


So I did update! Yay! Thanks to all those who favourited, followed, and reviewed. That was a big help in motivating me.

Side note: Chiyo's personality was originally nothing like what is portrayed so I apologize for any inconsistencies because ideas for her character outline are coming to me as I write and it's a little annoying.

Also, I apologize if any of the characters are OOC. I can't seem to nail their characters just yet.

Constructive criticism is greatly appreciated

Thanks for reading!