Previously: Mettaton dropped Frisk, Flowey and Deos into the "dungeon" by Mettaton and had to navigate the puzzle that was previously encountered in Snowdin, then Mettaton agreed to have an off-camera moment to be given a pitch for a show that is guaranteed to brighten the mood in the underground, revealing to him that Toriel is out of hiding, he also agreed to have some modifications done by Dr. Alphys against a threat that is worse than any human. Meanwhile, Cali and Dr. Alphys are working on a device that will allows Undyne to use D-T without melting, which she is forced to reveal that as Undyne walks in on this.
(Vision)
Deos sees a girl, the Yellow Soul child, who wasn't tied to traditional gender roles, she fancies herself a sheriff, something that other children didn't get, but she considered it to be unjust to be mean to them for no good reason, then one day as she was walking in the park, she was taken by some mad man, who took her to the top of Mt. Ebott in order to sacrifice her to the mountain. She fell down and immediately met Toriel, after some initial difficulties, she calmed down and followed her to her home in the ruins, she heard of Asgore and that if she meets him, she would be killed by him, but she decided that she should try to convince him to change his ways, it was better than staying here for the rest of her life doing nothing, especially as she found out that Toriel hasn't aged since she came there. She was able to get through Snowdin, Waterfall and Hotland...obviously Dr. Alphys was out when she passed through her lab...then once she got to just outside what is now MTT Resort, she was surrounded my various monsters, even though she wounded a couple of them, it was futile...
(MTT Resort)
Deos came out of that vision "She was taken as she was going to school by some mad man who wanted to sacrifice her to the mountain, in the end...she was killed when she was surrounded by a group of monsters, although she wounded a couple of them."
"They...didn't even meet Asgore..." Toriel said in shock.
"Who did?" Sans asked.
"The six that came before Frisk...hearing how each of them died and not by Asgore's hands...I cannot even force myself to hate him, not when I let it happen..." Toriel answered, then the tears started pouring out.
"Hey Tori, I know things haven't been smooth between you two, I know how it all started." Sans said, understanding more than he's saying.
"How did it start then?" Toriel asked him, wanting to know what he knew.
"Your kid died by human hands and not long before that, his adopted human sibling died, you both suffered from grief and Asgore had a lot of anger in him, now call him a fuzzy pushover all you want, but when HE gets mad, you know it's serious, the result...a whole load of hurt for any other humans that fell down here...at least until you two dropped in, all I'm sayin' is that if you have something planned that needs my help, I'm in." Sans said.
"Actually...there is..." Deos said, the others looking at him intently.
"What is it, Deos?" Sans asked.
"There was a dark presence that attached itself to Chara's soul, that's the name of that human, which was already attracted to that child's psychopathic nature before they fell into the underground, what I plan to do with Flowey will also result in that dark presence coming back as a by-product, we could use a glass cannon, I've already got Mettaton in on this and I'll be bringing the others of my Order here, so I know at least one that might be able to help you with what makes it possible for even Frisk to kill you in one hit, you might even survive two, I've seen the many variations of how it would've gone, if it was just Frisk, in the worst-case scenario, made possible by the fragments of this dark presence latching onto Frisk due to the walls of reality wearing down enough for them to reach out, you were one of two who stonewalled them." Deos said.
"Anything else I can do?" Sans asked.
"Gather Dr. Alphys, Undyne, Mettaton, Muffet and your brother, Mettaton needs to be there, the others...I want some witnesses for the first part of what I have planned...that and it'll give Muffet a chance to talk to Asgore and Dr. Alphys about getting the spiders from the ruins to warmer parts of the underground" Deos replied.
"I don't know what you have planned, but I trust you more than that weed you got there." Sans said.
"I don't see you being that open about yourself, smiley trashbag!" Flowey said.
"Don't push me..." Sans said, in a grave voice.
"That's enough!" Toriel shouted, while Frisk stood with her between the two.
"You're lucky that I have a deal with Deos and I do NOT want to provoke him, I've seen what he can do with Determination...talk to Undyne, if you don't believe me!" Flowey said.
"That's where I'm going, she'll either be Papy or with Dr. Alphys, I'll see ya a little later" Sans said, as he walked down the left alley, much to the confusion of all but Deos.
"He can teleport, I have a similar capability." Deos said.
"I gather that...shall we proceed to the Capital?" Toriel asked
"Yes...the finale of this story is getting close, we'll see if a happy ending for everyone in the underground is possible soon enough..." Deos said, as they walked into Mettaton's shrine to himself...There was a badly made fountain of Mettaton's box form spraying water onto the carpet.
"To the left is the restaurant where you have to reserve everything, even cutlery...to the right are the rooms of the hotel, most of which are occupied and in front of us is the way to the CORE, the elevator is occupied and the kiosk is staffed by 'Burgerpants', an overworked employee who sells sequin laden burgers that somehow provide nourishment...let's head to the CORE, which should hopefully be easier to get through, now that Mettaton has something worth showing...don't worry about Sans, he'll be fine" Deos said.
"Yes..." Toriel said, quietly, this didn't go unnoticed by the others as they continued to the CORE, they saw the blue walls past the light from the doorway.
(CORE)
They walked into the CORE and they saw a technological environment, full of artificial lighting, they see an elevator and two doorways on either side "The CORE, a geothermal power plant, created by W.D. Gaster, the previous Royal Scientist, which provides the power to the entire underground and more..." Said Deos.
"What would've happened if Frisk came here alone?" Toriel asked.
"Well, they would've had a harder time getting to the Capital, the right doorway leads to a fiery pit, the left doorway leads to the rest of the CORE and a load of monsters hired to kill them, then...the dance-off." Deos replied.
"Why not use the elevator?" Toriel asked.
"If they were able to use it, they wouldn't need to go through the rest of this place!" Flowey shouted.
"So, we should be able to use it, now that Mettaton has no reason to get in the way?" Toriel asked.
"Yes...unless our timing is different, Asgore is likely to be in the Throne Room watering the flowers, beyond that is where I need to be in order to break the barrier...but that can wait until we've dealt with everything else and no, Flowey...I haven't forgotten about our deal." Deos said, with a tone of caution, as they entered the elevator.
(Deos' Apartment / Lab)
"So with this, I can power up like Deos can?! Cool!" Said Undyne
"Yeah, but it won't be as strong as what Deos can do as you don't naturally have it, DO NOT use it too long or you'll melt like the amalgamates that you saw downstairs, I don't want to ruin your life, like I did with others!" Dr. Alphys said with a slightly angry tone, she needed to make sure that Undyne understood the risks of using Determination.
"Alphys, I've never seen you this fired up since you showed me THAT Anime." Undyne said, with some affection in her voice.
"Is that the one that brought her into a state of nerd rage?" Cali asked.
"Yeah! I thought she was cute like that." Undyne replied.
"R-really?...It's important to get this into your head, just because it's safer for you to use it, it doesn't mean that you should overuse it, Cali warned me about what's down here and we need to be ready for it, I've already made the modifications to Mettaton's systems, whatever we're dealing with, it won't know what'll hit it!" Dr. Alphys said, briefly stuttering, but quickly regaining control of herself.
"I'm taking a shot in the dark that you know that the presents are coming down hard here." Sans said, Undyne and Dr. Alphys turned around to see Sans there.
"I'm guessing that's Sans..." Cali said with annoyance coming from her.
"How long have you seen standing there?!" Undyne shouted.
"Long enough to get what Dr. Alphys has been working on, Deos wanted you two, Mettaton, Muffet and Papy to come with me to Asgore, he needs us to be there as some kind of witnesses" Sans said.
"I can understand why he wanted the rest of us, but why that psycho spider?" Undyne said.
"Psycho?! You're the one who's first diplomatic action was to throw a SPEAR at a child!" Cali said.
"Never mind..." Undyne said, slightly embarrassed.
"Deos thinks that she could get help from Asgore and Dr. Alphys to get the spiders from the ruins out safely...don't ask me why he wants to help her, maybe that's what her bake sale is for."
"Y-Yeah, but those prices are..." Dr. Alphys said, with Cali interrupting her.
"Please don't finish that sentence, Alphys! That's overused for its own good on the surface, never mind down there!" Cali shouted.
"S-sorry" Dr. Alphys said, embarrassingly.
"Well, we'll soon be meeting in person, so we can continue this later." Cali said.
"Does Deos know about what Undyne has?" Sans asked.
"N-No..." Dr. Alphys said, nervously.
"Welp...I don't know who's gonna have a bad time now, it might be Deos who is putting the grill on you." Sans said.
"Ugh...at least Deos doesn't go it on purpose, I might not be able to do much of anything right now, but keep up the puns and Undyne will be chasing you around with a spear, so can you please keep them until AFTER everything has become calmer?" Cali asked.
"Sure thing, I don't wanna use my arsenal too early." Sans said, much to Undyne and Dr. Alphys' surprise.
"You have an arsenal? FUHUHUHUHUHU! That's a joke! You're the laziest sentry ever!" Undyne said mockingly.
"I'll be honest, I've been hiding my true strength, until today, I've seen it as pointless as...well, I'll let Deos explain that one, he'll be able to back me up on that one" Sans said.
"Okay, bring us to where we need to be, before I think that both of you are crazy!" Undyne said as they're teleported via one of Sans' shortcuts out of the Lab in Hotland...
How will Toriel react to seeing both her old home and Asgore again? How easy will it be to convince him to not try and kill Frisk? How does Flowey fit into Deos' plans? Find out in Chapter 27: Mixed Feelings.