War Between Monsters and Humans
The ancient conflict that sealed monsters beneath the earth for a thousand years.
The War Between Monsters and Humans is the defining historical conflict of the Undertale universe, marking the end of surface coexistence and the beginning of monster imprisonment. It was a brutal struggle where humanity utilized weapons to overcome the magical prowess of monsters, resulting in the latter being sealed beneath Mount Ebott. This event set the stage for the entire narrative, creating the desperate need for human souls that drives the current plot.
- Conflict Type
- Species War
- Outcome
- Human Victory and Monster Imprisonment
- Location
- Surface World and Underground
- Key Mechanism
- Magic Barrier powered by Souls
- Status
- Concluded (Historical Event)
- Primary Casualties
- Monster Population Reduced to Few Hundreds
Lore & Background
The war concluded not with a treaty, but with a magical seal erected by human magic users. This barrier trapped all remaining monsters underground beneath Mount Ebott, cutting them off from sunlight and freedom. To break the seal later, seven human souls were required to be collected by the Monster King. This grim necessity shaped the politics of the Underground for generations, forcing Asgore Dreemurr into a role he never wanted as he awaited the seventh soul.
In Their Own Story
The old warrior stood at the edge of the cliff, looking up through the crack in the barrier where light used to touch the grass. His magic had faded with age, but his memory remained sharp. He remembered when the sky was open and humans were friends, before the swords came out and the fear took hold. Now, only the sound of dripping water echoed below, a reminder that the surface belonged to others while they waited in the dark for a miracle that might never come.
Reader's Guide
The conflict began when tensions between species escalated into open hostility across the surface world. Monsters initially held an advantage due to their magical abilities, but humans adapted with physical weapons and tactics. Eventually, humanity prevailed and forced all monsters underground beneath Mount Ebott using a powerful magic barrier. This sealing event cut off monsters from sunlight, forcing them to rely on human souls for survival and freedom. The war ended centuries ago, but its legacy persists as the central motivation for Asgore's plan to collect seven souls.
Did You Know?
- In Undertale, monsters turn to dust when killed; there is no canonical mechanic of regeneration upon reaching zero HP unless killed by a specific method.
- The barrier preventing monsters from leaving is maintained by human magic, not monster technology.
- Asgore and Toriel were king and queen before the war; Asgore remained king after the defeat, not becoming king specifically to lead after the war.
- Human souls are significantly more powerful than monster souls, which is why seven were needed to break the seal.
Frequently Asked Questions
What was the War Between Monsters and Humans?
This ancient conflict ended the era of peaceful coexistence between humans and monsters on the surface. It marks the historical moment when humanity drove the monster population out of their original lands.
How did humanity defeat the monsters in battle?
Humans used physical weapons to overcome monster magic, leading to a decisive victory for mankind. This strategy allowed them to overpower the magical prowess that previously protected the underground species.
Where were the monsters taken after losing?
The defeated population was sealed beneath Mount Ebott inside a magical barrier that requires human souls to break. They remained imprisoned there for roughly one thousand years until recent events began.
Why does this war matter in Undertale?
It established the rules of the Underground and created the need for seven souls, which drives the game's central plot. The desperation caused by this imprisonment defines the motivations of many key characters.
When did the fighting stop?
The battle concluded over a thousand years ago, leaving only hundreds of monsters alive to survive in exile. It is now considered a historical event that shaped the current state of both species.
More in Story & Timelines
Elsewhere in the Undertale universe
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record