Three Years Later...

Tatsumaki soared high above the destruction zone of A city, carefully watching and listening for any explosions. A demon class monster was spotted rampaging through the area, and the hero association, instead of calling a S class hero who actually lived near A city, decided to call her all the way in from Z city.

"Where is it?" she mumbled, coming to a halt. Not ten seconds ago she could hear explosions and screams from a mile away, but now, nothing. She could hear nothing but the crumbling buildings and the debris blowing in the wind. Though she knew she could easily handle this threat, she couldn't help but feel unnerved by the deathly silence.

She could only think of two reasons as to why this was happening: Either the monster was already defeated by another hero, or it had spotted her and decided to lurk in the shadows, waiting for her to let down her guard and strike when she was most vulnerable. She could barely stop herself from laughing at the latter, if this monster truly thought it could catch her of all heroes off-guard, then it truly had no idea who it was dealing-

"Damn iiiiiit!" a familiar howl reached her ears, causing her to groan in annoyance. This shout confirmed her first theory, a hero had already come by and slew the monster. She flew to the source of the noise, irritation beginning to set in.

"I swear, if he already killed the monster, I am going to..." she trailed off, finding a man in a yellow jumpsuit kneeling in front of purple blood soaked terrain. Her eyes twitched in annoyance as she landed behind the man, her arm raised above her head.

"Why? Why is it always-" and thwacked him as hard as she could. "...Oh, hi, Tatsumaki-chan," the man turned around, to find Tatsumaki wildly massaging her fist. "Ah, did you hit me again? You really need to stop doing that," he said as he took her hand in his own and gently blew on it.

"And you need to start answering my texts!" she replied, earning a questioning glance. "I texted you, asking if you were on your way! If you could just take a second to send me a yes or no, I wouldn't be wasting my time flying all the way to another city for no reason, baldy!"

"...Text message?" he mumbled, fumbling in his pocket for his phone. After a few seconds of digging around, he faced Tatsumaki with an apologetic smile. "Uh... Don't be mad, but..." he trailed off, showing Tatsumaki bits of pieces of what she assumed was his phone. "I think I broke it."

"...You think?" she repeated, resisting the urge to smack him again. Groaning in annoyance, she quickly ripped her hand out of Saitama's and began floating away from Saitama. "That was even a Nokia. How do you even break a Nokia?" she mumbled to herself, ignoring the buffoon that was following close behind her.

"Hey, what should we do about the kid?"

"The Hero Association will be here soon, they can handle her better than either of us."

"Mmm," he hummed in agreement, neither of them were good with people, let alone children. "Oh, that reminds me!" he said as he rummaged though his other pocket, before taking out a newspaper clipping and showing it off to Tatsumaki.

"...Recently orphaned children remind you of sales?" she asked, a hint of disgust in her voice. "Well, whatever. Seafood does sound good right now," she muttered, taking the clipping from Saitama.

"And it's in B-city, so it's on the way home!" Saitama said as he took Tatsumaki's hand in his own.

"Hey! You don't need to drag me, jerk!" Tatsumaki's screams of complaint was ignored as Saitama quickly made his way towards B city, unwilling to slow down in fear of missing out on such a great sale.

"That'll be four hundred and fifty yen!" the cashier said with a smile.

"Right," Saitama said, rummaging through his coin purse for the change.

"Come on, hurry up-" Tatsumaki was cut off as she felt the ground beneath her shake with great might. "Huh? What the heck was-"

"Ah, here it is!" Saitama said as he held out the coins. "Huh? She's running?" Saitama muttered.

"Probably cause of the earthquake, idiot," Tatsumaki said, floating in the air to avoid falling over. "It'll pass in a few-" she was cut off as a giant foot crushed half of the store, barely missing her by a few inches. "...Or it's a monster," she said with a shrug, watching as the giant, naked man raised his arm, preparing to crush the city.

"That looks like fun!" Saitama said as he leapt onto the monsters shoulder, causing Tatsumaki to sigh.

"This is why your fights always have collateral damage," she muttered as she flew in front of the giant, easily blocking his strike with a powerful psychic shield.

"Ugh! "Who are you?!" a man on the giant's right shoulder screamed, pointing his disgustingly skinny finger at her.

"Hmph! If you must know, I'm class S, rank 2 hero, Senritsu no-"

"Put some pants on," Saitama said, causing the giant titan and the man on his shoulder to glare at him.

"And who the hell are you?!" the man screamed, now completely ignoring Tatsumaki.

"Hey! Ignore the baldy! You're fighting me-"

"Hey!" Saitama screamed out at Tatsumaki. "Don't go around calling my 'baldy', midget!" he yelled out, earning a glare from Tatsumaki.

"Who did you just call a 'midget', baldy?!" Tatsumaki screamed, having half a mind to throw a skyscraper at him.

"How dare you ignore Beef Cake and I?! I'll make you pay for this!" the man called out, though he was ignored by both parties.

"I wouldn't have called you midget if you didn't call me baldy!"

"And I wouldn't have called you baldy if you didn't interrupt me!" Tatsumaki shot back.

"Well what did you want me to do? He's naked!" Saitama asked, pointing at the naked Beef Cake. "Speaking of which, seriously, dude. Put some pants on," Saitama demanded, earning a growl from Beef Cake.

"I... I..." he muttered, glaring at Tatsumaki as he raised his fist. "I am the stronge-"

"Whatever," Tatsumaki said as she flicked her finger, snapping Beef Cake's neck in an instant. "Well, that's over with-" causing him to fall over and destroy a large portion of B City.

"...Oops," Tatsumaki muttered, landing near Beef Cake's shoulder and next to Saitama.

"Aww," Saitama said, looking at Beef Cake in disappointment. "And here I was hoping for a strong opponent," he whined, before turning to Tatsumaki. "So, what now-"

"We run," Tatsumaki said, grabbing onto Saitama's hand and quickly flying the two out of there. "We run and we pretend we had nothing to do with this!"

Meanwhile, a nearby cowering man looked over the rubble and sighed.

"Oh, that was way too close," he muttered before picking up a nearby game case he dropped. "It's a good thing my "Adorable Little Sisters: Love is Forever" wasn't damaged. I don't think I'd be able to sleep at night if this got broken." and with that the man walked away, his head held up high as he successfully defended his new video game.

"So, have you considered going pro, yet?" Tatsumaki finally spoke up after having put significant distance between themselves and B City.

"...Now's not the best time," Saitama said, earning a groan from Tatsumaki.

"Oh, come on already! I'm tired of the Hero Association giving me credit for your work! It's making me look bad!"

"How is beating more monsters making you look bad?" Saitama asked, not at all understanding how that worked.

"Oh, I don't know, maybe because you destroy half the city whenever you fight?" Tatsumaki wondered rhetorically before turning to Saitama with a glare. "I keep telling them you're the one taking out those monsters, but they just think I'm trying to get you a high rank when you don't deserve it just cause you're my boyfriend."

"...But didn't you just cause huge collateral damage fighting that giant naked man?" Saitama asked, earning a glare. "And besides, you shouldn't worry about it," Saitama said with a wave of his arm. "You never cared what people said about you before, why now?"

"I don't care, it's just annoying hearing about it everyday."

Saitama stayed silent for the rest of the trip, mulling over what Tatsumaki said in his head. As they finally approached their house, he turned to Tatsumaki and placed his hand on her shoulder.

"Tatsumaki-chan, do you know why I have yet to register with the Association?"

"...Because you don't want to go alone?" she asked, earning herself a chuckle from Saitama.

"Eh, don't be ridiculous. It's nothing so petulant," he said with a smile. "It's for the exact reason the Association has been hounding you. As you've said, my fights often end with massive collateral damage. As a hero, I must defeat my opponents swiftly with minimal damage, so that the good people of this world could go on with their lives as if nothing happened. Until that day arrives, I have no right to call myself a professional hero," Saitama said, his voice filled to the brim with determination to achieve this difficult goal.

"...So you just don't want to register on your own? That's fine." Tatsumaki, however, wasn't buying his bullshit.

"...Heh, believe what you want," Saitama said with a smirk, though from the way he was darting his eyes about, Tatsumaki was sure she hit the nail on the head.

"Well, I guess it doesn't matter," she said with a shrug, choosing to drop the subject. "I'm going to go visit Fubuki. Don't do anything weird while I'm gone."

After a nice, peaceful day spent with her sister, Tatsumaki finally decided to head home for the evening. It was rare for her to walk around town with a smile, but her day out with her little sis had gone extremely well.

"I wonder if Saitama cooked dinner yet?" she asked herself as she opened the front door to their house.

Only to find a naked Saitama carrying around a broken down cyborg in desperate need for repairs.

"Hi, Tatsumaki-chan," Saitama said with a wave, as if nothing was amiss.

"...Who the hell is-"

"Is that your little sister?"

"Little?! Sister?!" Tatsumaki screamed, glaring at the broken down robot. "Now, listen here, you broken down toaster, I'm-"

"That's my girlfriend, Genos," Saitama said as he laid Genos down and walked towards the laundry room.

"Y-your girlfriend?!" Genos screamed in shock. "Sensei, no. Saitama! How could you?!"

"...How could I what?" he asked, confused at the disgusted look he was receiving.

"You know damn well, Saitama!" Genos screamed, lifting himself up with his one arm. "How could you take advantage of an innocent girl in elementary school?! Have you no-"

"I'm older than you, brat!" Tatsumaki screamed, slamming Genos into the ground with her telekinetic abilities. "What is with everyone thinking I'm a child?! Do I look that young to you?"

"...Yes," Genos foolishly replied.

"Oh, you're going to regret those words, brat," Tatsumaki muttered dangerously, slamming Genos against the walls of their house, cracking and breaking them in the process. Saitama looked on in despair as he watched his newly acquired house get torn asunder.

"Maybe I should have warned him beforehand," Saitama muttered, before shrugging the thought off. Saitama, due to years of experience of dealing with an angry Tatsumaki, knew exactly what to do in this particular situation. Quickly finding a decently clean pair of pants and a clean, yet slightly tattered shirt, he quickly made his way out the door, leaving Genos to his undeserved fate.

After a minute or two of running around different convenience stores, Saitama finally returned, trying his best not to let his broken down house get to him. "At least it's still standing," he reasoned with himself as he walked up to a now calm Tatsumaki.

"S-sensei," Genos greeted. "I apol-apolo-apolo-ZZZPPPT- I'm sorry for the misunderstanding earlier."

"Ah, no problem," Saitama said with a shrug, sitting down next to Genos. "So... You gonna be okay?" he said, poking Genos's exposed spine.

"Yes. Tatsumaki-Dono stopped before any serio-seri-seriou-ZZZPPPT- she stopped." Saitama was starting to think leaving Genos and Tatsumaki alone was a bad idea.

"I think I may have gone overboard," Tatsumaki muttered. "Why did you leave anyways? You could have easily stopped-" she stopped herself as Saitama held out a small lollipop.

"It took awhile to find one on sale," Saitama said as he unwrapped the candy and plopped it into Tatsumaki's mouth.

"If that is all it takes to calm Tatsumaki-dono down," Genos said, struggling to lift himself up. "I would have used my sugary treats dispenser."

"...You're what-" Saitama stopped, eyes widening as Genos's stomach popped open, dispensing chocolate bars and fruity delicious lollipops.

"He's like a living pinata..." Tatsumaki muttered, torn between whether or not she wanted candy from such a thing.

"Uh, Genos? Why do you have candy in your stomach?" Saitama asked, glancing over to see Tatsumaki's reaction. He had never seen her so indecisive.

"The Professor frequently gives me sweets to snack on when I'm out searching for information," Genos replied. "These particular sweets are about a month old-"

"Don't eat those," Saitama ordered, grabbing onto Tatsumaki's collar in case she tried to leap onto the pile of candy.

"Hmph. You're acting as if I have no self control," Tatsumaki said, sending a deathly glare at Saitama. "As if I'd eat something that was in some toaster's stomach," she said, slapping away Saitama's hand.

"Ah, my apologies," Genos said, scooping the candy back into his stomach. "I should have known better, please forgive me, Tatsumaki-dono," he said with his best attempt at a bow.

"Hmph, it's fine," Tatsumaki muttered, inwardly cursing Saitama to a fate worse than death, and mentally berating herself for letting such a delicious chance slip through her fingers.

"Ah, he's here," Genos muttered, doing his best to look behind himself. He turned back to Saitama and Tatsumaki, bowing to the two before crawling towards one of the shattered windows. "Thank you for allowing me to wait for Doctor Kuseno in your home, Saitama-sensei. I shall return for my training when my repairs are finished!" Genos proclaimed, throwing himself out the window, startling several passerby's and stray cats.

"...Training?" Tatsumaki asked, turning towards Saitama with a questioning look, to which he only shrugged.

"I dunno, I wasn't really paying attention when I was carrying him around." Saitama said as he got up and headed towards the kitchen. "I'm gonna go call the hero association. If I tell them we were attacked by monsters, do you think they'll repair the house for free?"

"Probably," Tatsumaki replied, not really caring. If worse came to worse, they could always move in with Fubuki, and Tatsumaki was fairly certain nothing would bring her little sister more joy than living with her older sister again.

Meanwhile, as Fubuki was sipping a cup of tea, a stray thought suddenly came to her. She didn't know from whence it came, but the irresistible urge to move into the smallest apartment possible just wouldn't leave her mind.