A/N: Before we begin, I'm gonna list off who's in the harem now and who will definitely be in later on.

The members are as follows:

Vaccine Girl

Subterranean Queen

Beast Queen

Mosquito Girl (Friendly Visits)

Those to come are as follows:

Tatsumaki (obviously)

Fubuki (also obviously)

Kombu Infinity (Seaweed haired monster in episoded 6)

Deep Sea Queen

That's all I'm saying at the moment. Others will join later on. Like the potential I'm adding today!

Also, I'd like to give a shout out to fellow Fanfiction member IcySnowSage for helping me with ideas for this fic.

Now. On to the story.


Citizens from all cities were lining up for a special occasion: The Hero Certification Exam! Many of those lucky enough to pass would be allowed to call themselves Professional Heroes, allowing them to earn money through donations for fighting monsters and conducting justice. And it was in one of these Hero Association Certified Test Sites that our favorite baldy and cyborg were taking the test.

Saitama waited patiently in line wearing nothing but a speedo, his sculpted physique on display for anyone bothering to look. Those that did look merely chuckled at him, thinking that his face looked really dopey, or that he was a weakling or such.

They were in for a surprise.

"Next, side-to-side jumps for 30 seconds! Ready?!"

Saitama got into position with the other candidates. His usual expressionless face immediately shifted to one of stone cold seriousness just before they shouted "GO!" Next thing the other candidates knew, they were seeing his body blur over that line faster than their eyes could follow. And the shocks just kept on coming.

The 1,500 meter run?

Passed in less than five seconds.

Weightlifting?

Single-handedly lifted more weight than any other candidate could hope to even attempt to lift.

Shot Put?

Threw that clear out of the building.

Vertical Jumping?

Got his head stuck waaaaay up high in the ceiling.

Whack-a-Mole?

No mole survived that day.

Punching Machine?

No contest.

The candidates would've stared bug eyed after that performance if they hadn't of already left with their tails between their legs. The only ones left in the room were the Hero Association Test Staff, and an athletic looking woman near the corner practically vibrating in place.

-With Saitama and Genos-

Both heroes-to-be were waiting patiently for their test results before Saitama got up from the bench he was sitting on.

"Are you leaving, Master?" Genos asked. "Your test results haven't arrived."

"I'm not leaving. I'm just heading for the bathroom." Saitama told him before leaving the locker room. He looked around the area before coming to a realization. "Which way is the bathroom?"

"I can lead you there!"

Saitama turned to see a tall, fit, and athletic looking woman smiling and waving at him. Her attire consisted of a sports bra and running shorts, both of which were made of tight fitting spandex, with a single running stripe on each side and the letter 'MZK' on her shorts. She also wore running shoes, a single earring, had her long hair done up with a scrunchie in a high ponytail, and medals hanging around her neck.

"Do you work here?" Saitama asked the woman.

"Nah. I was in the neighborhood and decided to drop in and see the candidates. Also, I used them not too long ago." the woman explained before holding her hand out. "By the way, I'm Captain Mizuki, Class-B Rank 74!"

"Saitama." greeted the bald hero-to-be as he shook her hand. "So, about the bathroom?"

"Right this way." she said with a smile as he waved for him to follow. The two began walking the halls before Mizuki decided to spark a conversation. "You know, you were amazing back there!"

"What do you mean?" he asked in confusion, earning a giggle from the woman.

"I mean I was watching you taking the physical test!" she said before turning to face him, her eyes wide and practically sparkling. "It was awesome how you destroyed all the events! Especially the 1,500 meter dash! I bet you could give Flashy Flash a challenge with how fast you were running!"

"Who?" Saitama blinked.

"The Class-S hero, Flashy Flash! Don't you know who the Class-S heroes are?" she asked, surprised that anyone wouldn't know who the Class-S heroes are.

"Not really. What's with the Class-S stuff?" Saitama asked before noticing they went past the bathroom. "Whoops! Hang on." he said before turning back and entering the bathroom. One moment of relief later, Saitama opened the door while throwing a paper towel before turning to a waiting Mizuki. "What were we talking about?" he asked as they headed back to the locker rooms.

"We were talking about Class-S heroes. Do you know about the Class System?" she asked while walking next to him.

"Not really. I only heard about the Hero Association just recently." he answered, much to her ever increasing shock.

"Wow! You're really out of it!" she exclaimed before smiling again. "In that case, I'll explain! The Hero Association has four separate classes that it divides us heroes into. The lower the class, the weaker the heroes. Class-C is the weakest. Class-B, which I'm in, is above that. Class-A is above that! And Class-S is way above that!"

"Really?" Saitama said before they reached the locker room. "Are they strong?"

"Super Strong! They're only called for impossible situations!" she said as they walked in, seeing Genos holding two envelopes in his hands.

"Master! Our results are in!" Genos said with a smile before noticing Mizuki. "You are Captain Mizuki. Class-B Rank 74."

"That's me! And you must be one of the other candidates!" She held her hand out with a smile. "Nice to meet ya!" Genos stared at the hand at first before reluctantly shaking it. When she let go, he handed Saitama his envelope before opening his.

"So how'd you do Genos?" Saitama asked.

"I got 100 points." he said, earning a gasp from Mizuki.

"A perfect score?! No way! That'd put you in the top tiers of Class-A easy!" she stated before standing up straight and shooting him a thumbs up. "And if that's the case, that makes you my senior!"

"I don't know what you mean by senior, but I'm afraid your estimation is incorrect." He then looked down at continued reading. "According to this, I'm actually listed as a Class-S hero!"

"WHAAAAT?!" Mizuki screeched before crowding around the cyborg. "No way! That's incredible! You must be super amazing! How strong are you?! Are you fast like Flashy Flash?! Are you strong like Superalloy Darkshine?! Which would you think is stronger between you and Drive Knight?!"

"Uh, Mizuki? I don't think he can answer if you keep asking that many questions at once." Saitama pointed out, causing the hero to blush and scratch her head.

"Whoops! My bad. I got excited." she chuckled sheepishly before turning to Saitama. "But what about you?! How did you do?!" Saitama blinked before pulling his papers halfway out.

"Hey! The letter also says that I'm-"

"Class-S." Genos finished, gaining their attention. "On top of that, the font size is bigger than mine." Saitama smiled at his paper while Mizuki looked ready to burst in joy.

"I can't believe it! Two new Class-S heroes in one day?!" she practically squealed.

"By the way, what did they ask you during the interview?" Genos suddenly asked, gaining Saitama's attention.

"Interview?" the baldy asked. Genos then began to explain how he'd been asked about the House of Evolution, along with it's destruction by intense firepower.

"I see. Perhaps your performance was enough that no interview was needed." said Genos.

"Of course not! Especially with how well Saitama did on the physical! Right, new senior?" Mizuki asked with a grin, only for and Genos to blink at Saitama's stiffened back.

"Master?" Genos said, hoping to get his attention.

"Don't tell me you didn't pass!" Mizuki muttered in trepidation. Saitama finally turned to face them, a forced smile on his lips and a dead look in his eye.

"I passed. But it looks like you're both my seniors or whatever since I'm a Class-C hero with a score of 71 points." he got out while holding up his test result.

"Whaaa?" Mizuki choked out in disbelief while Genos scanned the paper

"I see. Viewing only half the document, I mistakenly thought the top half of the C was an S." he explained.

"STOP ANALYZING IT, JERK!" Saitama snapped.

"This is totally unfair! Someone as strong as you in Class-C?!" Mizuki roared before reading the fine print. "AND PLACED AT THE VERY BOTTOM?!"

"It must be a mistake." Genos said, his voice as cold as most of his body parts. "I will speak to whomever's in charge."

"No! Don't! You'll just embarrass me!" Saitama pleaded. Any further arguement was cut off when a voice began speaking to them from the speaker in the room.

"Mr. Genos. Mr. Saitama. There'll be a seminar for successful candidates at 4 P.M. Please come to lecture hall number 3."

"Alright then. Come on." Saitama sighed. "All that really matters is that we passed. Let's get this over with." Saitama and Genos made to leave, only for Mizuki to stop Saitama.

"Wait! Where do you live?" she asked.

"What? Where'd that come from?" Saitama asked back.

"I wanna get as strong as you are!" she stated, her eyes blazing with furious passion.

"You are asking to be Master Saitama's desciple as well?" Genos stated in realization.

"Exactly! He may rank lower than me, but his strength far surpasses mine!" she declared. "Actually, I wouldn't be surprised if it surpassed all the other heroes in the Hero Association! Even those in Class-S!"

"Hmm. I don't know." Saitama hummed out, his chin resting between his fingers in thought.

"Pleeease!" Mizuki begged. "I'll show up on time to train! I won't give up! Just give me a chance!"

Saitama stared at the woman before him for a moment or two before shocking her when his face shifted to his more serious look.

"So you think you can keep up with my level of training?" he asked her. Mizuki blinked before straightening up and nodding in fierce determination.

"Whatever it is, I can take it!" she declared while pumping her arms. Saitama smiled, but was knocked out of his serious stated when Genos placed his hand on his shoulder.

"Forgive me for interrupting, Master Saitama, but we need to go now. The seminar is about to begin." he reminded them.

"Oh! I forgot about that." said Saitama before turning to Mizuki. "I'll tell you after the seminar."

"I can't! I gotta catch the train back home!" Mizuki pouted.

"Alright then. Come to my place in City-Z tomorrow. Your training will start then."

"Yes sir, Master!" Mizuki grinned, earning a frown from Saitama as she waved and left.

"Why does everyone keep calling me master?" he groaned before heading for the lecture hall.

'At last. I am now officially Master Saitama's pupil.' Genos thought with a smile before it dropped when something finally clicked.

"Master. What should we do about the others?" he asked, gaining the baldy's attention. "As a hero, it is her duty to destroy evil monsters."

"Oh yeah. I hadn't thought of that." Saitama blinked. "Meh. It's fine. After all, they're not evil. They don't try to hurt us or other humans, so it's fine."

-Next day-

Not fine. Not fine at all.

"PUT ME DOWN! LET ME GO YOU BIG, DUMB Cat!" Mizuki demanded as she swung her fists around. She was currently being held upside down by Beast Queen, her legs being held together in her left hand. "WHAT HAVE YOU DONE TO MASTER SAITAMA?! WHERE IS HE?!"

"Sleeping." Beast Queen yawned before lifting her up so that she could look Mizuki in the eye. "Which is what I wanna get back to."

"WHEN SAITAMA GET'S HERE, HE'S GONNA POUND YOU INTO A BLOODY PULP!" Mizuki yelled as she started pounding on Beast Queen's hand. "WHY WOULD MASTER SAITAMA LIVE OUT HERE ANYWAY?!"

"Cheap rent."

Both monster and hero turned to see Saitama walking up the stairwell and onto the roof, with the Subterranean Queen and Vaccine Girl shortly following behind.

"Let her go, Beast Queen." Saitama ordered. Beast Queen grumbled before releasing her legs, letting her fall to the rooftop before running towards Saitama where she spun around and got into a battle stance.

"It's three against two, Master, but I know we can take them!" Mizuki yelled.

"Saitama. Who is this woman?" SQ asked.

"Why'd she come here looking for you?" Vaccine Girl added.

"And why is she now calling you 'Master'?" Beast Queen finished.

Saitama just knew that he was gonna have his hands full explaining this one.


A/N: Next time, Saitama Vs. Genos. What did you all think of adding the newest hero to appear on One Punch Man to the fanfic? Please review.