Delta Rune

For the follow-up to Undertale of the same name, see Deltarune on the Deltarune Wiki.

The Delta Rune is an emblem representing the Kingdom of Monsters. It depicts an orb between two wings and three triangles beneath it, with the middle triangle inverted. It is first seen on a Boss Monster's robe during Undertale's prologue.

The emblem or portions of it can be seen in various areas and on armor. Certain monsters visually resemble it.

Symbolism

However... There is a prophecy.
The Angel... The One Who Has Seen The Surface...
They will return. And the underground will go empty.

Ancient glyphs in Waterfall

The Delta Rune is said to predate written history, and its original meaning has been lost in time. What is certain is that the bottom triangles symbolize the monsters of the underground. The winged circle is believed to represent "The Angel", foretold to be the one who has seen the surface and will return one day to depopulate the underground.

The Delta Rune's prophecy has two interpretations: one where the Angel frees the monsters by destroying the barrier, and a more recent one, where the Angel is an "Angel of Death" that wipes out monsterkind, "freeing" them from the mortal realm.

Dialogue with Gerson

• Oh yeah... The prophecy.
• Legend has it, an 'angel' who has seen the surface will descend from above and bring us freedom.
• Lately, the people have been taking a bleaker outlook...
• Callin' that winged circle the 'Angel of Death.'
• A harbinger of destruction, waitin' to 'free' us from this mortal realm...
• In my opinion, when I see that little circle...
• I jus' think it looks neat! Wahaha!

Gallery

• 
  The Delta Rune's appearance during the game's introduction.
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  The Delta Rune can be seen on few of the doors inside the Ruins.
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  The Delta Rune appears right above the door leading back to the Ruins.
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  The Delta Rune appears on the mysterious door.
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  Another variant appears in Snowdin's shop on a scroll.
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  The Delta Rune emblem at the Dog Shrine.
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  A variant of the Delta Rune can be seen on the wall in Gerson's shop.
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  The crest can be found above some doors in the CORE.
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  The Delta Rune appears above the Last Corridor entrance.
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  In the Last Corridor, the symbol appears on all of the stained glass windows.
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  The Throne Room has a throne with the Delta Rune crest on it.
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  The triangles appear on Froggit's chest.
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  The crest on Lesser Dog's shield in battle.
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  The Delta Rune can be seen on the armor of Royal Guards.
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  The triangles appear on Final Froggit's chest, much like Froggit.
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  The Delta Rune is the most prominent feature of Toriel's robe.
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  The wings and orb appear on the brooch of Asgore's cape.
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  ...And in battle, it appears on his chest plate.
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  Asriel's "God of Hyperdeath" form in battle, where it can be seen on his robe.
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  Asriel's final form in battle, showing much resemblance to the Delta Rune.
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  The appearance of Undyne the Undying resembles the Delta Rune.
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  The appearance of Mettaton NEO also resembles the Delta Rune.
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  The Delta Rune appears on the school doors in the True Pacifist ending credits.

Trivia

• "Delta Rune" is an anagram of "Undertale".
• "Delta Rune" may mean several things.
  • Delta is the fourth letter of the Greek alphabet, also known as "Δ". It reflects the triangles on the emblem.
  • "Rune" revolves around the meaning of magic, mystery, or spells. The monsters in Undertale mostly revolve around magic.
• The VHS tapes found inside the True Lab indicate that the fallen human's plan to free monsterkind was inspired by the Delta Rune's prophecy.
• The two interpretations of the prophecy Gerson cites reference the True Pacifist Route and the Genocide Route. In the former, Asriel destroys the barrier and frees all of the monsters; in the latter, the fallen human (by reincarnating via the protagonist) kills all of the monsters and erases the world.
• The purple arch on the Main Menu resembles the three locations that have an arch with the Delta Rune emblem:
  • Two are in the Ruins. The first one is in the area nearby the bed of golden flowers at the beginning of Undertale, and the second is past Toriel's Home in Home, leading to Snowdin.
  • One is past Asgore's Home in New Home, beyond the barrier.
  • Similar to the Main Menu, Flowey appears in all three areas atop the sunlit patch of grass.
• In contrast to most areas, the Delta Rune emblems shown on the entrances to the Last Corridor have the triangles inverted vertically. The triangles are depicted properly on the stained glass windows of the exact same area.
• The Delta Rune bears a resemblance to the royal crest of The Legend of Zelda series, both with three triangles and a winged figure.