Delta Rune

For the game, see Deltarune.

The Delta Rune is a recurring symbol throughout Undertale and Deltarune. It is featured most prominently throughout the prophecy.

Appearance

The symbol features a winged circle on top and three triangles at the bottom. The symbols varies slightly between depictions, such as the detail of the wings and the positioning of the triangles. The Delta Rune is often depicted as the crest of a shield.

The three triangles are typically depicted as equilateral or isosceles triangles, with the left and right triangles pointing up while the middle triangle points down. The middle triangle is often lower than the other two, but how far below the other triangles varies — ranging from the middle triangle being entirely below the other two (as in the game's logo), to the middle triangle being horizontally aligned with the other two (as depicted on Ralsei's castle in the legend of DELTA RUNE).

The Delta Rune symbol above the door of the Dreemurr residence has the triangles inverted vertically — the left and right triangles point down while the central triangle points up. In Undertale, the Delta Rune in the Last Corridor also has inverted triangles.

In the Original Game, doors that require the Ice Key have a Delta Rune symbol with a fourth, upwards-pointing triangle at the base of the winged circle, joined to the circle in a way that resembles a keyhole.

Symbology

Undertale

The Delta Rune as depicted in Undertale merchandise

In Undertale, the Delta Rune is typically depicted on a purple shield, in contrast to the black heart it is normally associated with in Deltarune.

In Undertale, Gerson tells the protagonist of a prophecy (distinct from the legend of DELTA RUNE) and how it relates to the Delta Rune symbol. He states that the triangles represent the monsters within the underground, while it is believed that the winged circle represents the Angel from said prophecy. Undertale's prophecy foretells that "The Angel" will descend from the surface and bring freedom to the monsters. An alternate interpretation is that the Angel is an "Angel of Death" who will "free" them from the mortal realm.

Deltarune

The rug in Kris's room in Castle Town, depicting the Delta Rune with colored triangles

In Deltarune, no explanation is given for the meaning of the Delta Rune. The three triangles may represent the heroes of the prophecy — on the mat in Kris's room in Castle Town, the triangles on the Delta Rune are colored like the heroes: the left triangle is pink (like Susie), the right triangle is blue (like Kris), and the lower triangle is green (like Ralsei). It is possible the winged circle represents the Angel's Heaven, following a meaning similar to that of Undertale's prophecy.

Usage

The Delta Rune appears in both the Dark World and Light World. In Hometown, it is often used in association with Hometown's religion.

Legend of DELTA RUNE

The Three Heroes banishing the Angel's Heaven (represented by the Delta Rune) in the legend

In the legend of DELTA RUNE Chapter 1 cutscene, the Delta Rune appears to represent the Angel's Heaven. In the legend, the Delta Rune appears above the earth during the section talking about the calamity that destroyed the earth, then appears in a pillar of light when the Three Heroes banish the Angel's Heaven.

The symbol itself also appears in a few other places in the cutscene. In the legend's introduction, the Delta Rune shield symbol appears on one of the castle walls, scrolling on-screen as "This is the legend of DELTA RUNE" appears. The Delta Rune also appears on Ralsei's castle in the legend's epilogue, but without the wings on the circle, as the wings behind the castle fulfill this role instead.

Light World

The Delta Rune appears in several places throughout Hometown.

• It appears above the front door and on the doormat of the Dreemurr residence. The Delta Rune above the front door has the triangles vertically inverted.
• It is depicted on the rugs in Kris and Noelle's bedrooms.
• It is depicted on the school's front door. However, as this is a double-leaf door, the opening between the two leaves causes the central triangle to be omitted and the left and right triangles to be partially obscured.
• Alvin's robe features the Delta Rune on his chest.
• Toriel's church outfit depicts the Delta Rune shield symbol on her chest, similar to her outfit in Undertale.

Additionally, the winged circle representing the Angel appears on top of the church's steeple and on top of the gate to the graveyard. The Angel itself is referenced by several townspeople, and is a central figure in the town's religion.

The shelter has an electronic lock, featuring three inputs with a symbol next to each: a pine tree, a police badge and the Delta Rune.

Dark World

The Delta Rune depicted on the glass walkway tiles in the 3rd Sanctuary

The Delta Rune appears frequently in Castle Town and the Dark Sanctuaries. In other Dark Worlds, it appears substantially less frequently.

• Castle Town
  • The Delta Rune shield symbol appears on surface of the castle's courtyard and the training area.
  • The Delta Rune shield symbol appears above the entrance to Ralsei's castle.
  • The wings from the Delta Rune appear on the borders of many of the doorways in Ralsei's castle.
  • In the Cafe in Chapter 4, if the musical performance has been unlocked, K_K's drum kit features the Delta Rune on the bass drum. (This is the same drum kit used by Susie in the Rock Video.)
• Card Kingdom
  • A Delta Rune appears on a door in the Field before Seam's shop, which is unlocked by completing the second Clock Puzzle.
  • A Delta Rune appears on the door leading to the Dark Fountain.
• TV World
  • In the Rock Video minigame, Susie's drum kit features the Delta Rune on the bass drum.
  • In the Original Game's Island Board, the Ice Key doors depict a Delta Rune with a keyhole-shaped fourth triangle.
  • In Mancountry, the angel symbol appears above the doorway to the temple.
• Dark Sanctuaries
  • Many artisanal windows throughout the Dark Sanctuaries depict the Delta Rune.
  • The glass walkway tiles depict the Delta Rune.
  • The doors in the Study feature the Delta Rune above the doorway as well as on the doors themselves.

Chapter 4's icon on the Chapter Select screen

Additionally, the Delta Rune is depicted on the Great Doors, which appear in several different Dark Worlds. It is also used as the icon of Chapter 4 on the Chapter Select screen.

The alternate spelling "DELTARUNE" (with no space) is used throughout Chapters 3 and 4 in both the Light and Dark World to refer to the Legend. This spelling is also used by Organikks, the Forgotten Man and the voice, albeit in a cryptic way that leaves its meaning unclear. The Forgotten Man and the voice mention that "DELTARUNE" is "waiting", a phrase which is also referenced in the DELTARUNE Announce Trailer.

Gallery

Legend of DELTA RUNE

• 
  The Delta Rune surrounded by a shield shape
• 
  The Delta Rune in the sky above the Earth, as depicted in the legend
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  The Three Heroes banishing the "Angel's Heaven" (represented by the Delta Rune) in the legend
• 
  The Delta Rune on Ralsei's castle in the legend, using the wings of the castle as the symbol's wings

Light World

• 
  The Delta Rune depicted above the door and on the doormat of the Dreemurr residence, with inverted triangles
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  The school, featuring a truncated Delta Rune on its door
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  The church, which has the winged circle of the Delta Rune on top of its steeple
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  The graveyard gate, which has the winged circle of the Delta Rune on its top
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  The Delta Rune on the rug in Kris's room
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  The Delta Rune on the rug in Noelle's room
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  The winged circle of the Delta Rune on an illustrated calendar in the church
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  Alvin, wearing a robe featuring the Delta Rune on his chest
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  Toriel's church outfit, featuring the Delta Rune on her chest

Dark World

• 
  The Delta Rune on Ralsei's castle, using the wings of the castle as the symbol's wings
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  The Delta Rune above the entrance to Ralsei's castle and on the courtyard
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  The Delta Rune depicted on the Great Door
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  The Delta Rune on a door in the Forest
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  The Delta Rune above the Card Castle door leading to the Dark Fountain
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  The wings of the Delta Rune decorating the doorways of Ralsei's castle
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  The Delta Rune on the rug in Kris's room in Ralsei's castle, depicting the Delta Rune with colored triangles
• 
  Susie's drum kit from the Rock Video, which features a Delta Rune on the bass drum
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  The door to the Ice Palace, depicting a Delta Rune with a keyhole
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  The winged circle of the Delta Rune above the temple doorway in Mancountry
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  The Delta Rune on the rug in the 8-bit version of Kris's room
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  The Delta Rune depicted on a glass tapestry in the Dark Sanctuary
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  The Delta Rune depicted on doors in the Study
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  The Delta Rune depicted on the window after defeating the Sound of Justice

Trivia

• The Darkheart Pin sold on Fangamer is the Delta Rune emblem depicted for the game's logo.