One Punch Boss

Chapter 5

The artificial monsters and their creator were lined up outside Genus' lab, keeping wary and terrified eyes on Saitama. Before said person could say anything, however, Genos jumped the gun. "Well done master. With their strongest monster defeated, eradicating the others and placing Dr Genus under arrest will be much simpler." He primes an arm canon, intent on incinerating the experimental creations who merely await death, knowing that if they try to escape, Saitama would kill them anyway.
Imagine their surprise when said arm gets crushed in Saitama's grip. "Slow down there kid. We have a really good opportunity here."
The members of the House of Evolution aren't the only ones who are confused. "Elaborate."
Letting go of Genos' wrist, he pats him on the shoulder. "There's a lot you don't know about how I run my city kid. Come on, everyone follow me."

Being led through the city, they were all very surprised by the multitude of monsters within the city and were doubly shocked when none of them attacked anyone. If anything they seemed... friendly. "So you gained unstoppable strength, took control of City Z, forced the heroes out and have since been incorporating monsters into your workforce?"
"Yup." He fixes Genos with a stern look. "There a problem?"
"No, master."
"Good." He turns to the stunned members of the House of Evolution. "Anyway, feel free to find work of your own, but I can help if you need it." He points at Mosquito Girl. "Except for you."
Said bug themed monster trembles under the attention. "M-me?"
Saitama nods. "Yep. My house can get a little dusty, and since you can fly you can get into the high up corners." Mosquito Girl sighs, relieved to be being given a task instead of being executed.

He waved them away. "Alright, monsters, do your own thing while I talk to the good doctor. And Genos, go to city hall to get registered. You set off a silent alarm every time you come to the city." As the others leave, Saitama loops an arm around the nervous Genus' shoulder and walks with him. "Listen, you're a smart guy, I recognise that, and my city could use a guy like you."
That shakes away Genus' nervousness and it gets steadily replaced with intrigue. "Really? You'd support my research?" The idea of having readily available resources, not to mention the multitudes of different monsters to test his ideas with was exhilarating.
"Of course. But," he gently grips Genus' shoulder to emphasise his point "I have a few rules. Any human or monsters you experiment on will be volunteers only, and you don't take any samples from anyone unless they say so. How do I put this?" He sees a roach on the sidewalk near his foot. "Let's say this bug is you. If you break my rules, or step out of line..." he lifts his foot and stomps down on the bug. Lifting his foot, it is revealed that not only did Saitama decimate the roach, but he had left an imprint of his shoe in the pavement. "We clear?"
Genus gulps, pure existential terror gripping his heart. "Crystal."
Saitama releases the doctor and smiles. "Great! Keep up the good work. Get all your stuff out of your old lab and I'll have Genos burn it down later."

Soon after that, Mosquito Girl became his live-in maid, Slugerous worked in the hospital, using telepathy to help with patients, Armoured Gorilla was assigned as Genus' bodyguard and assistant, Ground Dragon was assigned as part of the underground expansion alongside the Subterraneans, Frog Man settled well into traffic control, and Kamakyuri and Beast King were added on as a members of City Z's police force. All in all, good editions to the city.