Two essences in one body, it was never meant to last. Two weeks after monsters' freedom, the unlikely cohabitation between Frisk and Chara within one body starts breaking down. Frisk's body pays the price while both of their consciousnesses slowly start blending together. As they become a kind of human amalgamate, the two begin losing themselves more and more with each passing day.

Malory Wares is a massive Undertale fan, to the point she asked for Toby's permission to make and program a fan project of the fabled Hard Mode of Undertale. But when she uploads it, she is suddenly transported to the Underground, but in real life and no 8-bit graphics! But when she learns she has a soul filled with intelligence and magic, she must use them to go back home. Rated T

In a last ditch attempt to escape, Frisk, alongside her twin brother Harley, run up MT Ebott and leap into the Underground. What they find is not what they expect. Read as truths are revealed, enemies become friends, and the true threat to the Underground comes to light... F!Frisk F!Chara M!OC. Genocide Route First, Original story after Pacifist, No Marty Sue, M for Violence

What would you rather see? A skeleton and a human talking about magic? A king thinking over his decision on if he should let humans live underground? A flower who's hellbent on killing everyone and everything? Or perhaps a young aspiring guard working their patrols diligently. The side stories of their lives, chosen by our readers, reside here. Sequel to Two Worlds, Two Souls.

After sacrificing the souls to destroy the barrier and give everyone a happy ending, Asriel stayed behind in the Underground. He feared that, without a soul, he would hurt everyone as Flowey. But when a new human falls into the Underground he decides to help her out. And during their travels the duo have interesting encounters and discoveries in the now empty(?) Underground.

This is my full AU on Killer Sans. Let me know if you want info of other Sans's or any other Undertale Character! Please note that this is MY AU not canon Killer Sans. My Killer DOES have some canon facts on him though!

Frisk has Reset hundreds of times while searching for an ending that is just out of reach. When a run ends differently than any other, Frisk sees a chance to find the ending they truly desire and fulfill a promise they made long ago.

He wanted to SAVE her, so he gave up his SOUL. She never expected to be SAVEd, to be LOVEd, to be alive. Yet, there looms another calamity in the Underground One none expected to rise again from the battlefield. Charisk Tales - Part II of IV

And so it began. The SOUL that longed to rest on a bed of buttercups, under the sun Would do the last Fallen a favor, by ending their life as an offering To the ancient magic that locked Monsters on the Underground Charisk Tales - Part I of IV

"Third time is a charm", or so one would say. After their attempt at building Chara's SOUL, Frisk gave up life once more. Floating, guiding their own beloved in what should be a peaceful journey in the Underground. One last time, to SAVE them all. Charisk Tales - Part III out of IV

Eran las primeras vacaciones que se tomaba. Sans pensó que serian relativamente tranquilas, claro, si se ignoraba los gritos de su hermano, Papyrus, y el enamoramiento de este con Frisk; la molesta y deportista Undyne, intentando que se levantase del sofá y moviese el esqueleto; además de la familia Dreemurr, conocia a Toriel, pero sus hijos eran otra cosa. [Chara x Sans] [Chans]

Ever wonder why the legend says, "Those who climb the mountain never return?" This is our tale, the tale of the mages.

Chara has fallen into the Underground and Gaster has found a way out of the Underground and expects The King and Queen to do what it takes to leave but he does not expect what The King and Queen will really do nor does he know The Human's arrival. Come and experience how Chara grows into their new home and how Gaster will try to ruin it. (Rated K plus for now may change to Teen.)

Three times below the Surface. It took them three lives to honor their promise. A childish, innocent vow to the one they know and love, to friends, to a newfound family. They know they will be missed, but they cannot go back to the living world At least, not for now. Charisk Tales - Part IV (Final)

Undertale characters react to Man on the Internet's Musical. When something more sinister comes to their attention, what will they do? I do not own Undertale or Undertale the Musical.

For Monsterkind, the Surface represented freedom. For Frisk, it's a return to some uncomfortable realities. It all began with a simple wish. When that wish faded, Frisk tried to move on. Except, 'moving on' was not so simple. Emerging from the Underground had put them in a worldwide spotlight. From an unknown child, they had become an icon of great value.

"El jugador" ha muerto... Y ahora todos quieren JUGAR. En la peligrosa Ebott City, radica una constante inconformidad por habitar monstruos y humanos en un mismo lugar., desatándose conflictos delictivos que atentan con la vida de los habitantes. Sin importarle las advertencias de su madre, Frisk decide ir a la ciudad y tener su florería junto con su compañero y mejor amigo Flowey

What if two humans were in the Underground at once? What if one human was DETERMINED to stop the other? What if they could both SAVE? What happens when an Unstoppable Force meets an Immovable Object? When a certain scientist pulls enough of himself together, he finally finds a way to stop the destruction of his world. (Undertale AU. Rewrite of DT.)

An Undertale AU, where the Multiverse have created a creature that goes against nature. Read it to know what will happen. (My first story ngl)

Frisk had been pushed into a corner, he was blinded and was chased for a long time, it wasn't supposed to be like this! he was a prodigy that this Era of war needed. Alas, jealousy had killed one of humanity's hopes, Or has it?

The timeline was reset after a Merciless Run. As far as the monsters underground knew, it was just another ordinary day. But beings that no longer existed knew better. The key to either saving or destroying the world in its current state... is Alphys. (Contains elements of the Underswap AU's general concept and the Othertale animation.)

DIRECT SEQUEL TO "PATCHWORK SOUL" — A few months later. A family of monsters and their little human kid try to start life anew beyond the confines of a giant mountain. Maybe they find something. Maybe they lose something. Time flows ever onwards, but sometimes it goes sideways, and it's heavier than they thought.

(My own Underfell Take.) A lone human child falls into an underground world out for their blood... and their SOUL. With no friends except for a beaten-up flower, will the child be able to maintain their staunch pacifism? Or will they be forced to accept the motto of their new environment: "Kill or be killed"? (Rated T, just in case.)

Even after the barrier fell and the starved monsters found help and acceptance into the human community, Sans struggles to move on. But maybe things can get better. Even if all you can offer is steadiness and patience. Still, monsters are weird. You can see OC as any gender if you prefer. Kind with perhaps a patient soul. Warnings for panic attacks, PTSD, psychosis, injury.

I left my village to pursue science and magic. I left my village to see a better life than that of my own. I see the cities, I see the new technologies. Cars, lights, electricity. I see it all. And now, just a few weeks into my new life here in this big city, I wake up again living in my objective poverty. Now I must wake up again, to see more of this beautiful world.