"Sans! Alphys! It is good to see the both of you!"
"howdy, asgore."
"H-hi, your majesty."
"Greetings! This celebration is only just beginning. Feel free to help yourself to the food. The festivities will begin shortly."
Alphys cringed a bit. She was completely uncomfortable in these surroundings, and the fact that only yesterday the Human had been massacring the monsters made the jovial circumstances incredibly incongruous. ASGORE, of course, was just the type to shrug off the disaster as a minor setback, and since now it was literally impossible for him to die of old age, he had plenty of time to make up for his former mistakes.
"A-are you s-sure t-this is a good idea, your majesty?"
"You can just call me ASGORE. I believe I do not have much of a right to be referred to as a king anymore."
"Y-your majesty, after everything you've done for the U-underground, you will always be our King."
"I have done nothing for monster-kind. But please, enjoy the festivities. For better or for worse, we have won, and we are saved."
Alphys was actually quite shocked. ASGORE was showing genuine remorse and self-doubt. In all her 300 years of life, she'd never once seen ASGORE show even a hint of this sort of regret, save the period directly after ASRIEL and Chara's deaths.
She'd never seen him this shaken up. Perhaps this was what this "party" was for. Despite the mood, despite the monstrous catastrophe that had taken place, despite all the monsters who never came home, ASGORE still wanted to fill the Underground with hope. He still wanted to make everyone happy, and to make them believe that someday they'd get out.
Sans was looking around, giving of an air of happiness and supreme confidence. Monsters all around looked at him like they would some sort of god. Not a hero, not a superstar, and certainly not a buddy who hung with them at the bar sometimes.
It wasn't the way Sans liked to be looked at. All around, he saw monsters, clearly greiving, their tear-stained faces looking sadly toward the ground, toward the king or Alphys, or toward him. There was an impression of happiness, or at least the closest possible imitation, but none of them really felt good about any of this.
ASGORE noticed that the mood was clearly down, and he steeled his resolve for what came next. He'd been planning this since before he even announced the party, which was a long time for him.
"Attention! Attention monsters! Please, listen for just a moment!"
ASGORE cleared his throat and made sure everyone was paying attention before he spoke again.
"Now, I was not planning to make this announcement until later, but circumstances dictate that I must let this out now. I... have not been the king that monster-kind deserves. I was responsible for slaying those six children, and I was responsible for alienating my wife. The human who passed through here surely did so for revenge. To pay us back for the lives we've taken. Now, I do not believe that they were in the right, but... neither was I. And there is no question that I am the one responsible for the deaths that have occurred. On that note, I have decided that I can no longer continue ruling over this place. I have put much though on the subject, and I have decided that there is only one monster in the Underground who is worthy of taking my place. Our hero and savior- Sans the Skeleton."
At that, literally the entire Underground gasped together, all but Sans himself. He hadn't really expected this, but that wasn't to say that it shocked him. He wouldn't have put it past the king to make such a hasty decision. But he wasn't about to allow the decision to stick. He was no ruler. He was certainly no king.
"eh, sorry, asgore, but i can't really take the position. i'm not really the ruling type, and besides-"
"That is fine! Instead, I shall nominate our secondary hero and savior, the Royal Scientist and the one responsible for all of us still being alive- Alphys!"
And the Underground gasped even louder. Sans was genuinely surprised this time. Alphys was less of a ruler than he was.
"hey, uh, didn't you say i was the only one worthy?"
"Well, you are. But Alphys is still more worthy than myself. So she is the best choice!"
"K-king, I don't really think t-that t-th-this is a g-g-good idea!"
"Well, it is an idea you will have to live with. I am hanging up my trident and retiring to the RUINS. Unless Sans wants to take your place, you are now the Queen of the Underground."
"I... ASGORE, I never..."
"Cease and desist! My second to last order as king is to command you to rule the Underground to the best of your ability. My last command is to make you Queen. Congratulations, Alphys. You are now the greatest among your monster brethren. This is both a blessing and a curse. Make of it what you will. It was nice knowing all of you. Goodbye."
And with that, ASGORE DREEMURR, King of all Monsters, the Grand Spear of Justice, the Commander of the Underground, and the most powerful monster of all time stepped out of the room and began the short walk to the RUINS.
Alphys was in absolute shock. She had never, in all her life, imagined that she would become the Queen of All Monsters. Well. She had imagined it once or twice, but she'd always daydreamed about ruling alongside ASGORE, not in his stead.
"Oh my god. S-sans, you need to t-take my place. I c-can't imagine ruling over the U-underground! I c-can't handle this! Y-you need to-"
Sans looked around and saw everyone in the area surging toward them, questions ripe on their lips.
"maybe we should continue this conversation elsewhere."
Sans stepped forward and grabbed Alphys by the hand, disappearing into thin air once again, with her this time.
When they reentered reality, the were in Snowdin, nearly the other side of the Underground. Here, they were alone.
"Whoah. That was... S-sans! You need to become king! I... I c-can't do this!"
"welp. looks like you're gonna have to, 'cause i'm not doin' it."
"You can't do this, Sans! You can't do this to me!"
"i figure i'm savin' your life. you've got the underground on your shoulders. they rely on you."
Sans looked toward the ground for a moment.
"let me be straight with you for a second. i've had dreams about this before. everyone dies but a few monsters in hotland, and the human kills asgore and leaves. and it's just you. you can rule, alphys. maybe you don't think so, but you can. and if you agree to do this, to be the queen... i'll be with you every step of the way."
"Sans... I don't think I can..."
"see? it went from "i can't" to "i don't think i can." take just one more step. you've done it before, and you can do it again. we both know it."
"Sans, I was about to k-kill myself earlier today! I c-can't be r-responsible for a whole n-nation!"
"yeah, you can. one more step, alphys. one more. that's gotta be the motto, eh? one more."
"... Alright. I think I can do this. I... I can do this. I've got to- who are we kidding!? Y-you know I c-can't, I know I c-can't, we both know I-"
"can. you have to. alphys, listen. i didn't save the underground. you did. i saved two people, you saved more than seventy. asgore was right about one thing, anyway. you're more worthy of ruling this place than he is. you're certainly more worthy of it than i am, not to mention anyone else. sure, you've made some mistakes. but you had the guts to stop hidin' em when the chips were down. you had some skeletons in your closet, but they're gone now. they're in the light. and if that isn't real guts, i don't know what is. you're scared, alphys, and you think that makes you cowardly. you've made mistakes, and you think that makes you stupid. you've had some bad times, and you think that means life isn't worth living."
Sans took a step closer to Alphys and looked her straight in the eye.
"none of those things are true. alphys, you're courageous and genius and your life is worth it. never forget that. you couldn't save undyne, and i couldn't save papyrus. so we're alike. we have one difference, though. you do have the ability to do this. i don't. you're the ruler the underground needs, not me."
He grabbed both of her hands in his.
"and you can accomplish anything. so. go out there and check in with me in a day. if it's not worth it, then go ahead. end it all. but if i was right, you remember this. even if life tore you down to the bone, you've still got some real muscle left. you always will. you've saved this place once. don't give up on it now. undyne wouldn't have."
"Dammit Sans, you asshole."
Alphys had been quietly crying the whole time Sans was speaking, but now, chuckling through a sob, she gave off a ghost of a smile.
"You played the Undyne card on me."
Alphys took a step closer to Sans and wrapped her arms around him.
"Y-you know... no one's ever said something like that to me."
"eh, ya needed it, kid."
Alphys suddenly recoiled away from Sans.
"I... I, uh, g-got s-sorta en-enthusiastic!"
"forget about it. let's get back to the castle and see if asgore had the brains to leave his crown behind, eh?"
"Let's get this done."