Long time ago, female monsters ruled the surface along male humans(and female humans also). Out of the jealousy of the female humans, a war broke out between them and female monsters over male humans' preferences. Years of war later, female humans turned out victorious, forcing the female monsters to be trapped underground by a magical barrier created by 7 powerful human witches, never to see sunlight once more, or at least that's what legends and tales tell since hundreds of years. Present year, Mount Ebott, you, a male human climbed Mount Ebott, already with the knowledge that those of who climbed never came back alive. Once there, you fell into a big hole into a fall of about 10m, and for sure luck, surviving. This is how the tale starts, this is where the legend meets its savior, it's...the Undertale