Reset after Reset. Massacre after massacre.

Over 30 Genocide Routes have passed, and the human, under the control of a mysterious entity from outside our world, has shown no sign of stopping. The monsters of Mt. Ebbott are unable to do anything to stop it, as even their strongest and cunning warriors have fell to the Anomaly and its' DETERMINATION, being brought back to be slaughtered again and again for the Players' entertainment.

In the middle of all this is a skeleton monster named COMIC SANS, who was a former scientist and is currently King Asgore's Royal Judge. Having been the one monster who, through it all, always managed to be a roadblock for the human as the one person who stood a good chance of killing them many times and frustrate the entity pulling Frisk and Chara's strings. Despite his own power and intelligence, plus his knowledge of the other timelines, Sans was always eventually cut down.

But he was not the only one who held that knowledge... nor was he the only one still watching from the shadows.

As a new Genocide Route started, Sans was surprised to see that an old friend had returned... and that he had gathered all the BOSS MONSTERS of the Underground to help Sans defeat the Anomaly once and for all. The familiar enigmatic figure had shared with everyone the memories and experiences of all the previous timelines; The massacres, the resets, the cruelty...

...but most importantly, the entity behind it all, and the importance of the humans they knew as their friends and family that the Player was using as its' puppets.

Gathering his allies and drafting new plans, Sans battles the Entity one last time, leading them throughout the Underground as he lure them into a well-crafted trap.

But... when Sans arrives at the CORE, no worse for wear, and the monsters spring their trap, something happens with the great machine - and all of a sudden, Sans, the Player, and a number of other monsters are transported to a new world where the very principles and laws of reality and magic they all knew are turned on their head.

Scattered across this new realm, Sans along with his friends, family, and fellow monsters must work with the natives of EQUESTRIA to defeat the Player - before it's too late.

This is my first story in years. I've been rather inactive as of late. Not the most motivated to write all that much, not to mention I don't see myself as a very good writer (I mean, I'd say I'm decent at writing, at the very least). I hope I can write a good story that everyone can enjoy. This is story is also somewhat of a goal for me, and it's not just any old Undertale crossover. No, this is not an Undertale AU story - although I may put some references to them here and there as I progress - but rather, an Undertale Alternate Timeline (AT) story. I'm (going to be) mixing elements from all sorts of prominent timelines; the three most significant ATs being Last Breath, Disbelief, and Call of the Void. I may simply forego listing both Last Breath and Disbelief later on as there is an AT called Help From The Void, which is a mashup of the two, with elements of Rejuvenation. Another timeline I will include will be No More Deals, which will be critical to Chara's, Frisk's, and The Player's plotlines later on in this story (a big goal of mine in writing this fic). I'll also include minor nods to some other timelines here and there; I can guarantee you that Dusttale and UT: Hardmode: Wonderful Idea will make some form of an appearance here.

If you haven't played UNDERTALE yet, I really recommend you to check it out first and play through it before reading this story, so you know the main characters and storyline. Warning, the game contains flashing lights and fast moving images. Play at your own risk.

Undertale is by Toby Fox and Temmie Chang.
MLP: FiM is owned by Hasbro, conceived by Lauren Faust.