The War of Humans and Monsters was a legendary clash long before the events of Undertale.
Monsters were too weak to put up a fight; the soul of nearly every monster combined is only just as strong as the power of one human SOUL. Countless monsters were massacred, without a single human casualty. Few monsters survived, one of which was Gerson. Eventually, the monsters surrendered, and the humans emerged victoriously. The humans gathered seven of their best magicians and sealed the monsters under Mount Ebott with a magic spell.
After the war, the monsters retreated into the deepest part of the Underground, which would be called, "Home." After a period had passed, fearing the humans no longer, they populated the rest of the Underground and settled their capital in a place they would call "New Home".
Monsters mostly blamed the war on humanity and took a vengeful look on humans as a species. This bitterness, especially after the death of Asriel and his adopted sibling, led King Asgore to declare war against humanity, installing a policy to kill all humans that fell into the Underground and eradicate humans once the seven SOULs needed to break the barrier are collected.
- ↑ "A monster with a human SOUL...
* A horrible beast with unfathomable power.
* The humans, afraid of our power, declared war on us.
* They attacked suddenly, and without mercy." - Ancient Glyphs in Waterfall
- ↑ "* Humans are unbelievably strong.
* It would take the SOUL of nearly every monster...
* ... just to equal the power of a single human SOUL."- Ancient Glyphs in Waterfall
- ↑ "* Not a single SOUL was taken, and countless monsters were turned to dust..." - Ancient Glyphs in Waterfall
- ↑ Hey! That's the store of Gerson, The Hammer Of Justice! He's the toughest monster that ever lived! He fought in the War of Humans and Monsters.... And he survived! He's a true hero! - Undyne when calling her outside Gerson's store
- ↑ "* Seven of their greatest magicians sealed us underground with a magic spell." - Ancient Glyphs in Waterfall
- ↑ "* Trapped behind the barrier and fearful of further human attacks, we retreated.
*, far into the earth we walked, until we reached the cavern's end.
* This was our new home, which we named...
* "Home."" - Book at Toriel's Home
- ↑ "* Fearing the humans no longer, we moved out of our old city, HOME.
* We braved harsh cold, damp swampland, and searing heat...
* Until we reached what we now call our capital.
* "NEW HOME."" - Book at Asgore's Home
|Plot Elements|| Boss Monster • Delta Rune • Echo Flowers • Golden Flowers • Player • SOUL|
The War of Humans and Monsters • Determination • Barrier