Ending (Neutro)
To get this ending, you must kill Toriel, Undyne, and Mettaton, and spare Papyrus. In this ending, through a process of elimination, Papyrus becomes the King of the Underground. Sans is the one who takes care of all the paperwork and told his brother that Asgore, Undyne, Alphys and Mettaton went on vacation.
Ending (Geonocida)
To reach the genocidal ending you have to kill a certain number of creatures, as well as the bosses. You can see the requirements in the list below. You must reach the following numbers of defeated enemies (you can check these numbers in the SAVE points), as well as the bosses in each area: Ruins: 20 deaths (Toriel)
Ending Pacifista
To reach the pacifist ending you cannot kill any creature, and you also have to save and leave with all the main characters you encounter. Doing this will unlock new content, so we recommend trying to reach this ending the first time you play Undertale
