After sans destroyed every set of timelines and every eternity in the universe he was eventually forced into calming down to think about his actions. After the equivalent of 3 days time sans was now calm and decided to check for any signs of chara. There was nothing remaining in the entire universe that could prove chara existed aside from the spirits of everyone he killed in his set of timelines. It seems the raw power of his rage erased chara from existence in this universe. It was just a few seconds later that sans realized that without chara or frisk still alive. or at least not connected spiritually with him. The universe couldn't regain time that easily and without time there isn't truly any possibilities and without those possibilities the universe lacked hope.

And without hope nothing will succeed or have a good or bad outcome. In other words despair is a form of entropy. And magic is one of the only things in the universe remaining that has a chance to return entropy back to how it was before the end of time. And yet that still would require waiting as even the afterlife's working together are having trouble undoing the entropy sans unintentionally created. In the end The cooperation of the afterlife's wasn't enough and the gods had to giving sans the soul of virtue and the ruler of the underworld had to give sans the soul of sin. Both of which are in the remaining hope that by some miracle sans could someday figure out how to fix this mess.

The ruler of the void chose to give sans a blessing that would give him immunity to insanity. Again in the hopes for making sans have an easier time fixing his mistake. After those were given to sans he began to practice using multiple soul traits at the same time while he still could in the universe. He was slowly beginning to make progress and discovered that certain traits such as hate and kindness were incompatible with each other on their own. But can be compatible if you add an unrelated trait into the mix that is capable of acting as some form of mediator for the traits in question. He also began to understand the power contained within the soul of virtue was raw power in the form of divine magic and the sin soul is the same but for demonic magic.

Eventually sans was able to use this newly gained power to leave the universe. And it was just on time too because as sans left the universe. The universe fell to entropy. Luckily before sans left the universe he learned to create a force field and created a force field around his universe that was made to contain entropy. He didn't know if it would help protect the multiverse forever but knew it would at least be enough for him to have a decent chance to fix it someday. But for now sans had a New problem. where should he go so he can learn more of his power