Possession (Gaster x Sans Fanfic)

When skies are grey

The showers definitely put a damper on things. Your family erupts into a mixture of moans, laughs and 'I'm so proud' s at your pun. It's light and should clear soon so the activity still has the go ahead by Safety Inspector Mom. She made sure everything was ready and prepared. You had been planning this over your many RESETs, trying to get things perfect and not risk another RESET so this moment lasts. You had planned to do this in the first time you got to the Surface but when Sans made his announcement, you were heartbroken and Chara managed to convince you to RESET.

...

You saw how it hurt Sans. You couldn't stand it when you saw him outside of the Ruins. You took the coward's way out and RESET. Chara told you you couldn't hide and offered to take control so you wouldn't get hurt. They told you not to fear him but to take control. They told you to hurt others so he couldn't hurt you. They told you a lot of things. They weren't right. It wasn't Sans's fault. You remember them manipulating you into hurting others and the fear they caused you to feel so you would strike. The. Monsters. Down. So you would strike Papyrus down. But not Sans. You couldn't hurt Sans. They had originally said no one else would be left to take him away. You weren't sure how much you wanted that, but, when you were in Snowdin, you saw his face and thought you'd lose him if you just stopped. You wanted him to be yours but you knew it was wrong. But you kept going. After Papyrus, you wanted to stop but, by then, it was too late. Chara was in control. The more they slaughtered, the more submissive you were. What was the point in trying? Then Sans tried to stop you and you fought. Then he spoke about timelines and you stopped. He was baring his SOUL to you. You began to fight Chara and took back control, but you kept fighting. You kept trying to beat him. You were curious. You wanted to know all his secrets. When he stopped saying new things, you RESET. Chara kept coming back and you thought they had stopped, finally. Turns out you were wrong.

"kid?"

You had stopped during your internal monologue. Coming! Just thinking.

"heh, you're a kid. wait until later in life to become a worrywart. for now, be a kid."

You hug Sans. Guess you matured quickly Underground. Older than you look and all that stuff.

"yeah, i gotcha. anyways, let's catch up to the others. this mountain ain't gonna climb itself."

You ask where his puns are at.

"can't pull the wool over your eyes. heh. just thinking to but i'm sure I got a mountain of jokes stashed away somewhere. just want to stay grounded since i've been a little rocky recently."

You laugh. The skies are grey but you're happy. You grab Sans's hand and imagine for a moment, you're holding hands, before beginning to eagerly drag Sans up the hill.

You look back at the shifting shadows. They resemble that thing in Waterfall. You have an idea about who that was. You smile and stick your tongue out at him, making sure Sans doesn't see. The shadows disperse back into their normal shape, but not before you see the anger on the face of that thing. Ha, looks like you were right. You win.

Sans's locket jangles on its chain as you drag him up the mountain. He really does make you happy when skies are grey.

When skies are grey? When skies don't exist, yes. I may not be able to leave but I can still watch. That damned child knows! And they still gave him that locket! They may say it is a best friends thing but you know better. That brat will suffer.

...

But they don't matter. Not right now. They will suffer when Chara finally breaks them. They want this timeline to last so they won't continue RESETting to try and rid themselves of Chara's influence. This time, that time travelling tyrant is trapped. Ha! You win this time. All he has to do is be patient. Wait for Chara to come back with that child's SOUL and allow him to leave. All he has to do is wait for the child to break and then he will be free. He will roam and help Chara and get what he wants. They will be safe when Chara moves onto the next world. And he will help.

Just wait for when skies are black child.

Your world is closest. Don't worry, you will receive peace reader.