Delta Rune

The Delta Rune is an emblem representing the Kingdom of Monsters. It is 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 introduction scene, and secondly on Toriel's robe, foreshadowing her role in the story. The emblem or portions of it are depicted in various areas, armor, and occasionally, monsters visually resemble it.
== Symbolism ==
The Delta Rune is said to predate written history. However, the original meaning has been lost in time. What is certain is the bottom triangles symbolize the monsters of the Underground. The winged circle is believed to represent the "angel," which is prophesized to be the one that has seen the Surface and will return one day to depopulate the underground.
This prophecy has two interpretations: one where the "angel" destroys the barrier and brings freedom to the monsters, and a more recent outlook on it, where it is an "Angel of Death" that kills everyone in the Underground, thus "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 ==
 Once Upon a Time soundtrack.png | The Delta Rune's appearance during the game's introduction.
 Ruins location Middle Road Puzzle.png | The Delta Rune can be seen on few of the doors inside the Ruins.
 Snowdin Forest location Ruins door.png | The Delta Rune appears right above the door leading back to the Ruins.
 Mysterious Door location.png | The Delta Rune appears on the Mysterious Door.
 Snowdin Shopkeeper screenshot shop.png | Another variant appears in Snowdin's shop on a scroll.
 Dog Shrine location PS4 empty.png | The Delta Rune emblem at the Dog Shrine.
 Gerson screenshot shop.png | A variant of the Delta Rune can be seen on Gerson's wall.
 CORE location.png | The crest can be found above some doors in the CORE.
 Last Corridor location.png | The Delta Rune appears above the Last Corridor entrance.
 Last Corridor sprite window.png | In the Last Corridor, the symbol appears on all of the stained glass windows.
 New Home location Throne Room.png | The Throne Room has a throne with the Delta Rune crest on it.
 Froggit battle idle.gif | The triangles appear on Froggit's chest.
 Lesser Dog battle idle.gif | The crest on Lesser Dog's shield in battle.
 Royal Guards battle.png | The Delta Rune can be seen on the armor of Royal Guards.
 Final Froggit battle idle.gif | The triangles appear on Final Froggit's chest, much like Froggit.
 Toriel battle.png | The Delta Rune is the most prominent feature of Toriel's robe.
 Asgore Dreemurr overworld.png | The wings and orb appear on the brooch of Asgore's cape.
 Asgore Dreemurr battle idle.gif | ...And in battle, it appears on his chest plate.
 Asriel Dreemurr battle God of Hyperdeath.png | Asriel's "God of Hyperdeath" Form in battle, where it can be seen on his robe
 Asriel Dreemurr battle final form.gif | Asriel's Final Form in battle, showing much resemblance to the Delta Rune
 Undyne the Undying battle.gif | The appearance of Undyne the Undying resembles the Delta Rune (Much like Asriel).
 Mettaton NEO battle.gif | The appearance of Mettaton NEO resembles the Delta Rune (Much like Asriel).
 Surface screenshot school.png | 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, as the monsters mostly revolve around magic.
* The prophecy states that when an angel appears, the underground will be empty. This hints at the two main routes to beat the game, in which Asriel Dreemurr may destroy the barrier and free all monsters, or the first human (by reincarnating through the protagonist) may kill all of the monsters and erase the world.
* The purple arch on the Start Menu is implied to resemble the three locations that have an arch with the Delta Rune emblem:
** Two are in the Ruins:
*** The area nearby the bed of Golden Flowers at the beginning of Undertale.
*** The second is past Toriel's Home in Home, which leads to Snowdin Forest.
** One is past Asgore's Home in New Home, beyond the barrier.
** Similar to the Start Menu, Flowey appears in all three areas atop the sunlit patch of grass.
* In contrast to most areas, the Delta Rune emblems depicted on Last Corridor's entrances have the triangles inverted vertically. The triangles are depicted properly on the stained glass windows of the exact same area, so this may just be a mistake.
* The Delta Rune bears a resemblance to the royal crest of The Legend of Zelda series, both with three triangles and a winged figure.
== References ==
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