This is my Dusttale: Obsessed Monster take. Since it was not intended to stray too far from the canon and instead fix what I disliked about him, I simply refer to it as "Obsessed Monster Reimagined". Essentially it derived from my other Reimagined dust timeline "Carnos Reimagined DustDust". Essentially after Dust failed and the human reset, his DT caused an anomaly in which his LV reset from Max (twenty) but his stats didn't and he was still considered to be LV twenty but was displayed as zero so he could achieve LV twenty again, but the more he climbed over twenty the more his body deformed and mutated to be monstrous. This takes place after that iteration fails and another reset takes place, enhancing the anomaly a little by making Dust remain the abomination he's become, resetting his LV again but not his stats, and removing the progression cap. Essentially Obsessed was able to climb to LV twenty and keep gaining LV stat bonuses even though his LV remained twenty, so it's like he could still gain LV but it wouldn't show more than twenty. Obsessed Monster never used souls in this au, instead he wanted to defeat the human without the help of souls, he wanted to crush them, to become the new soul of determination and see them suffer as he makes them feel a fraction of the suffering and helplessness he's felt. Sans makes a device and hides, waiting for the human to reach the barrier, and as they do he initiates the device while they're passing through, firing the power of the souls through the human, not killing them but creating a short power burst equivalent of seven human souls, destroying the barrier, allowing Sans to escape while the humans left unconscious. By the time the human awakens, the world has fallen, Sans has personally exterminated all life, both man and beast alike. The human would progress out of ebot and into a ruined city, the sky black from the new moon night. Eventually they'd encounter this newly deformed horrifying Sans, his voice borderline demonic, deep, distorted, and dark. Sans and the human battled, the human struggled but somehow managed to cut him down. However, when Sans was struck to zero, he uttered the words "Did you really think it would be that easy?" Before fading to dust, however he was not dead, the abomination that was Sanses true form, the eldritch horror he had become, appeared on the horizon with it's claws gripping the side of the world, as if holding it steady from orbit. This abomination opened the terrifying maw upon it's chest as it slowly charged a blast, red light shining from it's chest, the humans eyes filled with nothing but unbridled terror as the beam fired, eradicating them and the world. With this, Sans reset, and if the human ever returned, he would grant them the same hell again, and again, and again.