This universe is set in a soulless neutral route. Frisk/Chara had killed everything several times and the last timeline, Frisk's heart suddenly opened and they spared Sans. And they promised to never come back. Currently Sans is stuck in a infinite anti-void where Frisk reset and quit before the game properly loaded. Borntale used to have a different name but Sans renamed it, and he would CREATE. Of course, he didn't know how to, so he attempted to remake something...anything. He succeeded. He created Born!Frisk and Born!Chara. But all he created was their existence, so they wouldn't be much trouble yet. Eventually he created every other monster's EXISTENCE. Now all he needed was a vessel to hold all their existence and form a body. But he was worn out from creating "existence" so, he had a break. While he was sleeping, the "EXISTENCE" entered his soul, because existence is drawn to any sort of vessel. He woke up managing to stop Frisk, Chara and Asriel's souls from entering his soul. He was overwelmed by all the EXISTENCE within him, but tried to contain them as he created souls for them.
Eventually, he was tired AGAIN. So, he attempted containing all the EXISTENCE in one vessel, while Frisk, Chara and Asriel got their own vessels. He eventually went to sleep. Upon waking up again, he felt like himself once again. but when he looked toward the vessel that contained most monsters EXISTENCE, it was gone. Concerned he checked on Frisk, Chara and Asriel who were now slowly forming into bodies. Relieved that nothing had happened to them, he kept searching for the missing vessel, to no avail. Returning to the three nearly formed children, he found the missing vessel. He quickly grabbed it, and kept it from escaping. But instead of "escaping" the vessel broke, and the EXISTENCE became a disarray of colous, souls and EXISTENCE. Born, prepared for the situation, used his soul to encase the EXISTENCE. But he only caught a portion of it. The rest, disappeared. Born couldn't be bothered to look for them.
He had a job to do first.
Frisk was the first one to be "born" from existence. Then Chara, then Asriel. The three were kept seperate, due to their fragility. Born created a TRUE LAB kind of place, and kept them safe inside. He noticed that Chara was lacking some DT. So he gave a portion of his soul to Chara, who's DT increased dramatically. He put Chara and Asriel together, just to see if they would get along.
They became "best friends".
He decided to create someone to be "best friends" with Frisk. But he couldn't think of anyone to create, so he made ---
(Working in progresss)