Sans watched the fight between the human and his brother from behind the trees. He saw his brother standing with open arms, trying to bring out the good in the LOVE filled child. The child approached and Sam's couldn't tell if the smile on their face was one of innocence, or the smile of a psychopath. The smile wavered. The small child gave a sniffle, and then the knife clutched behind their back fell to the ground. The kid ran forward and collided with Papyrus, sobbing. Sans exhaled in relief. Stepping out of the trees, he embraced the two. "Come on, kiddo. It's getting late, let's find you a place to sleep."
The kid looked up at him arms raised above their head in the universal "carry me." Picking the child up, he started home. By the time he reached home, the kid was asleep. Still not fully trusting the little one, he took them to his room. With the use of some magic, the room quickly became presentable. He set the child on the bed. He started to leave the room, stopping at the door when he heard the kid whimpering.
"No! don't hurt them Chara, don't leave me alone again." Sans paled at the name. What did Chara have to do with the child? Sans returned to his bed, curling protectively around the kid. He didn't know if he was protecting the seemingly innocent child, or if he was protecting everyone else. The kid shifted, and it took Sans a moment to realize they were crying into his hoodie. Whoever was the cause of this... They were going to have a bad time.
A quick one-shot created with Google speech to text. Might become more, but probably not.