Undertale One-Shots x Reader (DISCONTINUED)

DT (Gaster)

(okay please tell me the picture is good cuz I drew it and I think it's bad but maybe not I don't really know I'll shut up now thank you for your time)

"Gaster, I swear if you don't open this door right now I'm going to break it down!" You were incessantly beating on the currently locked door to the lab you shared with W. D. Gaster. He had called you earlier, and he told you that's where he was and that he wanted you there as soon as possible. However, he wasn't answering the door, and you getting really angry. Was this some sort of joke? You had actually been sleeping good for the first time in weeks, and then you were rudely awakened by the phone. You were just about to roundhouse kick the door when it finally slid open, revealing one out-of-breath Gaster.
"Sorry. I ran up here. We have got to install an elevator if we're going to keep this lab underground." You laughed at how out of shape he was.
"Well maybe if you spent more time coming back up the stairs instead of going down and just staying down there, it wouldn't be a problem." He had been spending way too much time down in the lab. He claimed he'd been working on a "game-changer".
"I think I will be, (y/n)! I've finished it! Come see!" With that he raced back down the stairs. You followed him down the stairs slowly. He met you at the bottom, now wheezing from running up and down all of the steps. You laughed at him again, but it faded as he briskly walked away from you. You quickly followed after him, your steps barely able to match his long strides.
"So when you say you finished it, I'm assuming you mean the DT machine?" Asgore had asked Gaster to work on a machine that could extract the determination from human souls. Asgore was hoping that this determination could be used to enhance the strength of monsters, and bring them back from the dead. After the deaths of Asriel and Chara, the King and Queen wanted anything to get them back. But the King had overstepped with the idea of killing human children and extracting their determination. Both you and the Queen had thought so. Toriel was planning on leaving to go to the Ruins to live, and she wanted you to go with her. You were still extremely indecisive. On one hand, science was your favorite thing. Murdering children, not so much. And you liked to spend time with Gaster. He wasn't just your lab partner, he was your friend. But if you left with Queen Toriel, you wouldn't be forced to help out with that terrible experiment. You hadn't discussed this with anyone other than Toriel, but you contemplated it daily.
"Look at it. It's beautiful." Gaster had stopped in front of a large machine that bore a great resemblance to a friend of yours from Snowdin named Giftrot. Large aluminum tubes were coming off of it in places, and a long metal box stuck out from each end. On a large television screen, there was a human soul displayed.
"Gaster, where did you get that soul?" There had been a human living with Gaster's son, Sans, just outside the lab. You knew that they were considered a soul with the main trait of kindness, but every human child had underlying attributes of determination.
"The human that had been staying nearby passed through Waterfall. Undyne was more than happy to take care of it once Alphys asked her to." You froze in shock. The kindness soul had had a plan to get everyone out of the underground without killing anyone, and now that's never going to happen. You could feel angry tears well up in your eyes.
"You IDIOT! How could you kill her? She was planning on saving us!" Your mind was moving too fast for you to make coherent statements. You were stumbling on your words, but Gaster still got the point.
"(y/n), I'm sorry. I thought... I wanted to make you happy. I didn't know you cared so much about the human." Gaster seemed confused towards the fact that anyone could care about a human. He had disowned Sans over the same matter.
"Gaster, that was a KID! You helped murder a child! How would you feel if someone did that to little Papyrus?" Gaster's other son, who was still an toddler, was the light of Gaster's life. Sans cared deeply about his little brother too, and had been hoping to take him away from their father, who had on occasion experimented on Sans with determination. You couldn't help but agree that at times Gaster was dangerous.
"Gaster, this is the last straw! I'm leaving!" This helped you make up your mind pretty quickly about going to the Ruins. You started grabbing all of the equipment that was yours around the lab. Gaster kept trying to protest, but you ignored his feeble attempts to stop you. You had gathered everything up and balanced it precariously in your arms when Gaster blocked the sole exit out of the lab. He stood at the bottom of the long staircase with sadness evident in his face and voice.
"Please don't leave me, (y/n). I need you here. You're the reason I keep going. You're the reason why I built this. Not because Asgore told me to, but because I thought you might be impressed by something I actually did. Please stay. I- I love you. I need you." You stared at him in shock. There's no way he could possibly mean that. He just doesn't want to lose his lab partner, right? Silence filled the room, and eventually a sigh of defeat released from Gaster.
"I guess I can't stop you, then." He stepped to the side, leaving an opening for you. You didn't move from your spot, still gaping at Gaster in distress.
"If you want to leave, then do it. Don't just stand there and make me think you care." You could see the sorrow eating away at Gaster.
"I'll stay." A look of hope hit the scientist's face.
"Just let Sans keep Papyrus. I don't want you to ever see either of them again." This was the final straw for Gaster. He broke down, tears streaming down his face. He now had to choose between his child or the person he loved. You could see him trying to decide, and then he suddenly walked out of the room. You stood there, confused. He walked back with a squirming toddler in his arms. He handed Papyrus to you and quietly asked you to give him to Sans. There was a note tucked into Papyrus's shirt pocket, but it was folded so you could not read it. Gaster gestured for you to head out the door. You reluctantly nodded and walked up the stairs, leaving all of your equipment behind. You reached the small shack-like watch post Sans had built for himself by the "official water fountain of Hotland". He was currently snoozing with his head on the stand. You set Papyrus down and tapped Sans on the shoulder. He glanced up at you, confused. You simply nodded once and walked away. Papyrus frantically started screeching goodbyes towards you, and you felt tears trickle down your face. Papyrus was almost like your own child. Both he and Sans had been part of an experiment to bring the royal children back, and after that was considered a failure, Gaster had turned to the DT machine. You knew you were probably not going to see either of them ever again. You headed back to the lab and stood outside the door for a little bit. You saw a flash out of the corner of your eye and turned to see Sans holding a now silent Papyrus.
"thanks for what you did. i uh, i appreciate the sacrifice. i hope that you can still be happy, stuck with that creep." Sans had also been like a child to you, and even though he was only in his early teens, he still was more mature than most anyone you'd met.
"He's not a creep, Sans. He cares about you two." You couldn't help but feel remorseful, and you started to turn back towards the lab.
"wait, (y/n). if you need a place to go after this... dadster said we've got a place in snowdin. you can always come live with us."
"Thanks, Sans. That's two offers to leave this place, but I don't think I'll ever get away. This is where I am meant to be." You could feel your eyes welling up again.
"then at least promise you'll come visit us. papy loves you, and i do too. you're like the second parent we never got. please, don't forget." You could only nod, and notice that Sans also had tears slipping down his cheeks as well. You wrapped the two skeleton brothers in a long hug, and then turned to wave a goodbye at them.
You went through the tall metal door and down the long flight of stairs. You were greeted at the bottom by a bittersweet Gaster. He gave you a hug and you collapsed in his embrace, finally giving in to the sadness. This was not how you were planning the day out. But as the tears stopped and you looked up, you could tell Gaster was truly happy. He loved you. You reached up and gave him a swift kiss, which left him extremely flustered. You laughed at his bright blush, and things felt just like they used to. As time went by, you never touched the DT machine. But you had found love in a man who had seemed incapable of feeling the emotion. And you couldn't deny that you loved him back.

(IM SO SORRY THAT ONE TURNED OUT SO DARK IM SORRY PLEASE DON'T HATE ME FOR MY RANDOM SADNESS)
(I guess I always thought that "oh no my stories aren't affected by my current state of being" yeah NOPE the depression is very obvious in this one)