N/A: This one's placed a few months after Genos takes Saitama to Kuseno's lab, and reluctantly accepts the adult as his disciple.

Unbeta'd, so sorry for any mistakes（*/｡＼*）.

Genos-sensei was amazing. For the few months Saitama had being under his tutelage, he had confirmed time and time again this truth.

After waking up in an unknown place, Saitama met the doctor that had saved his sensei's life a year prior. The old man, Saitama was sure, didn't like him much from the very beginning, more so since Genos-sensei disappeared from the lab to retrieve the brunette's belongings. The silent treatment that followed would've bother Saitama if it weren't for the note his sensei left about where he was, who the doctor was and not to do anything to further his injuries. So Saitama had obediently stayed on bed, waiting for his sensei's return.

"Saitama," called the blond, snapping the adult from his reverie. "wake up and move, we don't have time for your daydreaming."

The mad cyborg could be close, thought Saitama what younger didn't say, walking behind him in silent awe. Genos-sensei usually kept to himself, addressing Saitama only for basic stuff, but the adult didn't mind. His sensei was amazing for his young age, and Saitama's devotion to him only grew bigger after the doctor had finally told him a little about his past and his current quest to avenge his family.

How could he stay strong enough to fight for others when he was in so much pain was mesmerizing, and his gentleness towards the weak spoke volumes of his kind heart. Of the environment where he had grown until tragedy snatched it from his hands. Genos-sensei was amazing, and Saitama swore to himself to never leave the boy's side.

"Sensei, the doctor sent a message", Saitama brought the shining screen up to show the cyborg.

One of the few tasks Saitama brought upon himself, was to be on the good side of Doctor Kuseno, and one way to achive so was to keep the man updated on his adoptive son. Genos-sensei usually went on his way, updating his status only on emergencies or once to twice every couple months; ever since Saitama came along, though, the brunette kept updating the man at least three times a week (which earned him his own mobile phone and a credit card from the man; not that his Sensei really knew about the latter as requested from the good doctor).

Genos, looked back, remains of what used to be a huge rat monster covering the landscape before them. Saitama had stayed back as ordered from the cyborg; even though he'd wanted to land a few hits, the boy kept saying he wasn't ready, and that it would end with him recovering at the lab yet again (after doing excatly that a couple times, the brunette couldn't really argue). He had watched the fight from afar until it was over, just to almost glue himself to the cyborg's side.

Letting a small sigh escape his lips, Genos reached for the phone and read the message; only to tense his shoulders, a dangerous gleam in his eyes, brows frowned together. All in a matter of seconds.

"Get back to the lab", ordered the teen cyborg, turning his back to Saitama, as he started fast-walking the opposite way.

"Wha-But!", stammered the adult, shocked by the sudden mood-chage of his sensei. He quickly read the message and realized the reason behind the other's mood, eyes wide with worry. "I'm coming too!", he stated, running to catch up with the younger.

"I said. Get. Back.", spat the teenager sans looking back.

"Sensei, please! Let me be there for you! I can help", there was no way Saitama was letting his sensei go alone for this; not if he could do something. "I know I can help-!"

Genos stopped and turned brusquely, a death golden glare directed to the brunette. His sensei was stuborn, Saitama had learnt that much after his time following him, but Saitama was his disciple, and was ready to take in everything his sensei had to teach, personality included. So he stood his ground and moved before the blond could say anything.

Saitama's arms rested upon metallic shoulders that were too hot to be comfortable immediatly after the fight, but the adult ignored it on behalf of what his sensei needed. Genos-sensei generally was selfless and kind, even if a little somber, the only times this chaged were when the Mad Cyborg came up; still then, he didn't think about himself, but about avenging those who had died at his hands no matter the cause. Genos-sensei had never said it out loud, but the Doctor did, to drive Saitama away from his sensei. Too bad it only increased Saitama's veneration for the teen.

The cyborg was as tall as Saitama, his frame a little wider because of his arms. Saitama rested his chin next to his neck, unsure as to what to say, but thankful the blond didn't move away. It wasn't like him to do this kind of thing, but he couldn't ignore the fact that his sensei was still a teenager; Saitama still remembered how life could suck at that age, and Genos-sensei's wasn't any easier.

"Please", he murmured, "don't do this alone. Don't make me leave you to this alone."

A low hiss escaped Genos' body as his vents opened to release some steam, metallic hands grasping fleshy shoulders, forcing the older away from himself. But he didn't let go, Saitama noticed, pinned down by the angst and hatred reflected in too human eyes to be synthetic. He didn't moved, wouldn't have been able to if he wanted; the grip on his shoulders bordering on the painful side.

"This isn't your figth, this doesn't have anything to do with you," the boy said in a clipped, almost mechanical tone. "This isn't your fight".

Saitama knew. He did. Just as much as he knew it wasn't the boy's fight every moster he had annihilated so far on his quest, nor be a silent hero, nor save anybody's live. Genos-sensei didn't need to go around the world doing heroic acts, nor take resposibility of useless, unemployed adults who only were good to be on the recieving end of punches and kicks in any battle they engaged. That didn't mean the blond would stop any time soon.

"I know," he said at last, hands setting at each side of his sensei's face, trying to get the message through. "I know," he repeated quietly, "but let me be there for you. Sensei... you don't have to do this alone. I don't doubt, not even for an instant, that you can handle this alone. Sensei, you... your amazing and strong, and I know you can defeat any enemy that comes your way, but... please, don't do this alone."

"Saitama..." the young cyborg studied Saitama while the man tried not to squirm before such an intense stare. "How can you, being an adult, stick with me and call me sensei, when all I am is a war machine ready for battle at any given moment?"

"Sensei...!"

"I know," interrupted the cyborg, "You've said it before; I'm still human below all these weapons, right?," he sighed loosening his grip, eyes still fixed on the other man. Saitama looked back, brows furrowed in worry. "Stop with that look, heroes aren't supposed to look so young and vulnerable, specially adult ones," he admonished poking the adult frown before turning around.

Saitama regarded the younger's back in awe, fumbling in his backpack for his old recorder. "Sen-Sensei! Repeat! Repeat that, please, Sensei!", he pleaded as the blond started walking away again, at a much slower pace.

"You already heard me, so record it yourself. And hurry up, we have to get there before nightfall."

Saitama's eyes brighten to the blond's words, and did as told, a cheery yes falling from his lips as he rushed to catch up with his sensei.

Extra:

"... 40... 41... 42..."

"What are you doing?"

The sudden sound of the blond's voice broke Saitama's concentration and the brunette face-planted on his sweat. Genos' eyes scanned the adult; heartbeat quite elevated, heavy, unstable breathing, general bodyheat elevated, muscles strained.

"Se-Sensei!", Saitama sat in a terrible seiza, but Genos didn't mind, it was the thought counted. "I- mmh... I mean..."

"You were over doing it again, weren't you?". At the guilty look on his disciple's face, the blond tiredly sighed. "I've told you... " he began, but stopped at the adult's self-disappointed expression. "Just... don't take too long, we're yet to find a place to pass the night."

"A-Uhm... Yes!" Saitama said looking up to his sensei with bright eyes. "About that, there's a lady you saved earlier today who offered us a room to stay the night if we're ok with sharing," he provided, a slightly nervous tone in his voice.

"Very well, then. Let me know when you're done to head there, alright? I'll get dinner in the mean time."

"Yes, Sensei!"

Genos turned and walked away, shaking his head to his disciple's antics. The man was an adult, and still look so young with the light of admiration he had every time he looked at Genos. It was weird and a little embarrassing, but it wasn't so bad as days went in and out, making the man a welcome change in the teen's life since that day. Maybe having a disciple wasn't as much a burden as he had initially thought.