Disclaimer: I do not own Undertale and any of its characters. It is owned by Toby Fox. I also do not own the other characters made by their respective artists that will be appearing in the story. I only own the plot of the story, my created characters and the created places that I would be using in this story.
TK!Sans is a character made by perfectshadow06
This meeting happened before captain Sans witnessed Frisk's final moments at the cliff.
She felt another presence just a little distance behind her. It felt slightly familiar. "Sans?" but it wasn't familiar enough. "No, it seems like another visitor from another place." she turned to face them and saw a skeleton that looked a lot like Sans, only younger who wore a blue jacket, shorts, shoes and googles. She gave him a small smile as she regarded him with careful eyes. The way he dressed was a bit odd. Not like she hasn't seen anything of the sort for the past weeks. He kind of reminded her of how she and Ink met. "It's good that you saw me in one of my better days."
The soft breeze that caressed his face suddenly stopped as she spoke. Out of nowhere feelings flowed into him like water from memories that flooded his mind unexpectedly. Her smile, how much he liked to tease her, how she clung to him when she got scared, how he got jealous every time she was with another man, how he almost died of fright with the stunt she pulled at the circus, how he kissed her on the head while she made a wish on the first star, how they had danced, how he loved her... And the feeling of hurt seeing her in pain the following days after, because of his own doing. "What... happened?" he asked, with no self introduction whatsoever and went on asking away. This didn't happen to him before.
Still staring at him with a neutral smile, she answered him, "You have not introduced yourself yet and you're already asking me a question?" Her defenses slowly broke at his reaction and she giggled. He looks cute when he panics. "It's alright, I'm not the strict type."
"My name is... Sans." He noticed something shining on her hand as the sun's light touched it. He eyed at the knife placed firmly on her hand. "What are you going to do with that?" A knife in the hands of anyone with a clear sign that it wasn't to be used the way it should is never a good sign.
"I assure you it's not to kill anyone… well, one in particular. Not like you'd be able to call me a single persona anymore." she looked at the knife smiling sadly.
His eyes grew wide at her statement. She was just kidding, right? But that smile told him otherwise. "Frisk, no. Don't you dare do that."
"They never found a way to rid of this. This was the only way, the only solution we've come up with. Please don't cry." She laughed, not at his crying state but at the humor of her not so far off demise. "This is what happens when children travel to other realities." she said coming close to him so she can wipe the tears off his cheeks.
"I'm not crying and I'm not a kid. After all the things I've been through, I consider myself mentally mature." He wiped at his face as he tried to stop his tears from flowing. Why is it that some of the good realities requires someone to give up their life? Why can't they all just live happy without sacrificing the life of another?
"Is that so?" She said as she wiped his tears away, "Well then, be strong and go home. I don't want you to see what's to happen next."
"But you would… you would-!"
"Please, Sans. Do this for your sake and mine. You should never face this kind of experience."
Chara appeared beside Frisk along with the other six souls and looked at him, a sad smile on her ghostly face. 'This sorrow was never yours to endure.'
"I'd want to tell you something, if that is alright with you." She smiled at him awkwardly, "You know, in case he were not to reach me in time." he nodded agreeing. She lent her face close to his ears — or where they should have been if he had any and whispered to him, "I love you, Sans. That can apply to you as well." She faced him again and laughed slightly at his blushing face, opening her eyes in the process which showed a clock that wasn't in motion. Was she somehow the one responsible for stopping the flow of movement, of time here? Of the memories that came to him all so suddenly? He stared at her, his tears now put to a halt. Maybe she did that to prevent changes that might happen to her reality with their meeting. But the feelings, he still had no clue if it really was her doing it. Even if she weren't the one responsible, what was the purpose of it? "See, your tears have stopped." She kissed him on his forehead and hugged him tightly before standing up and backing away a bit. "Now go, hurry along." She waved him off. He opened a time portal still looking at her. She smiled and waved her hand to him, giving him a last goodbye before turning around and walking back to her original spot. He stayed there for a few more minutes and after a while slowly turned his back to her as well. "Sans?" He stopped, "Don't look back." everything went back to the way it was as tears started to stream on his eyes again. He entered, not looking back, fulfilling his silent promise to her.
He couldn't stay away for long. When he came back, she was gone and all that's left was a crying Sans on the edge of the cliff. It hurts, it hurts a lot. Not wanting to disturb this Sans' grieving, he went back inside the portal and silently closed it... a single tear trickling down his cheek.