After that particular event, it was business as usual, with the first order of business being the lord of the deep currently in Saitama's office. Deep Sea King is naturally wary of the being before him, since he not only tanked several of his punches but also effortlessly thrashed around the Deep Sea King in his hydrated state, automatically making him a deadly threat in his current shriveled form. He has to play his cards right to see what this human wants. "You said to come here if I wanted to make our lives easier?"
Saitama leans back in his office chair to put his feet on his desk. Classic power move. "Of course. I'm the most powerful man in City Z, and you're the most powerful Seafolk in the ocean. Why not benefit one another?"
Deep Sea King was quick to respond. "Because humans are a race of vermin."
Saitama's previously carefree expression quickly morphs into a stern one as he puts his feet down and sits straight, interlocking his fingers on his desk. "May I remind you that the "vermin" you're talking to kicked your ass and won't hesitate to throw you out of my city if I have to. So play, nice."
The reminder of his humiliatingly easy defeat at the hands of a human left Deep Sea King aggravated, but compliant. "What do you propose?"
Smiling once again, Saitama extends his offer. "As a leader myself, I know I wouldn't send my people to war without provocation. I propose, I solve the root cause of this little conflict, and we become mutual partners. Now then, what's the problem?"
The Deep Sea King points an accusatory finger. "Humans leave our oceans filled with your filth and trash. You have any idea how many times I've left my home and seen turtles choking on plastic bags, or fish caught in your plastic rings?"
Saitama hums. "That is a problem." He snaps his fingers. "Tell you what," he starts signing a few forms, "I'll send you a few of my underwater guys to help, and maybe Vaccine Man, he's big on environmental stuff like this. He'll be happy to help."
Deep Sea King is taken aback by how agreeable this human is. "Uhh."
Saitama hands him the papers. "I look forward to our future as unlikely partners. Get those to city hall and you'll be ready to go." Deep Sea King gets up after a moments hesitation and nods at Saitama out of respect before leaving.
With that out of the way, Saitama started filling in another form. He would need a way for his people to get to and from the home of the Seafolk, so he was making plans for a reflecting pool to be made. On the surface it would look like a normal reflecting pool, but in reality it will be an underwater tunnel to the home of the Seafolk. He would need it to be given the ok by Deep Sea King, but Saitama is confident he will agree.