They're Just Words.

World 1-♾

As the final battle came to its end, Bowser lay defeated on the cobblestone floor of his castle, Mario looming over him with a fireball in hand.

“Go on”, Bowser spat, giving him a dirty look, “Finish it.”

Mario looked at him with tired eyes for a minute and sighed deeply before extinguishing the flame.
“I'm not gonna kill you, Bowsey.”

He sat with his back against the wall, pulls a cigarette pack from his dungarees and puts one in his mouth before lighting it up with the fire flower abilities. Bowser looked in stunned silence as Mario paid him no mind and simply smoked.

“Are… are you mocking me?”

“Far from it… I'm just tired of it all.”

Bowser raised an eyebrow. “Of what?”.

Mario took a long drag before puffing smoke back into the air, filling it with the scent of tobacco.
“Bowsey… have you ever wondered why you're always after Peach? Even though you're anything but compatible?”

“Well, that's easy. Because I want to rule over the Mushroom Kingdom.”

“Right. But, do you need her for that? You've got the manpower, a good enough legion under your command; heavy artillery to seize the kingdom by force, and of course, lack of opposition because the people of the mushroom kingdom dont fight. So… why do you need her?”.

Bowser tried to answer, but couldn't come up with anything. He racked his brain reverently, and yet… nothing.
That was odd.
Why did he need Peach anyway?

“No idea, I'm guessing?”Mario puffed, “Then I'll tell you why. It's because the code demands it.”

“The… what?”

“You ever heard of ‘Nintendo’, Bowsey? Well, I don't expect you to anyway. I'm the only one that stays self aware. To put it simply, they're our makers. All this rivalry, war, kidnapping, fighting and adventuring… it's all for nothing. We were made for entertainment, and that's it.”

Bowser was waiting for Mario to make the punchline, but the dark, solemn expression on the plumber's face spoke volumes: this was no joke.
He was too stunned to speak. What would he even say? What could he say? The whole thing made no sense to him.

“You know… this isn't our first meeting.” said Mario, a sad, twisted smile on his face. “72 times. That's how many attempts it took me to get here and finally defeat you, and you were responsible for about 53 of my deaths. Somehow though, I remain self aware each time, and I'm not even talking about my lives in different universes. I can't begin to count how many different professions I've dabbled in. I'm just supposed to be a plumber…”

He had barely completed his sentence before he broke down in quiet, painful sobs.

Bowser looked at him and wondered which of them had truly suffered defeat. If he were to believe Mario's words, that would mean he had lived through an incredulous number of deaths, and he found himself feeling nothing but sympathy for the man he called his enemy.

“So…” Bowser asked cautiously, “what happens now?”

“I… I defeat you, save the princess, and the story ends. For now at least. I'm sorry I've gotta do this to you Bowsey… you're a victim of the system… we all are. It's not fair to you, your Goombas, your Koopas, and all your other minions.”

“Ha!” Bowser laughed weakly as he got to his feet, “The day my nemesis has to worry about my well being is a clear sign the world wants to end. We fought, and I lost. And on this rare occasion, I'll be a good sport to you.”

He made his way to the edge, looking at the pool of lava that bubbled beneath, and tumbled forward.

Mario hurriedly got up and approached the edge, just in time to watch him hit the magma and have his pixelated body cease to be. He sat upright for a moment, before taking down his hat and putting it on his chest, honoring the koopa King one last time.

“Well Mario… the princess awaits”, he said, fixing his hat back on his head as he made his escape from Bowser's crumbling castle. 
“Let's a- go, I guess.”