Underfoil is a Sub-AU of EntropyTale in which the characters are much more evil than their original counterparts. Underfoil is more of a complete opposite than simply corruption, with the exception of a few things being taken out or added. After Asriel killed Chara and took their SOUL to the surface, only to underestimate the humans and die, Toriel wanted vengeance, and to go to the surface to kill humans. However, Asgore decided to honor Chara's wishes and didn't instate a policy to kill all humans. Toriel is furious upon this, and runs away to the RUINs to kill humans and overthrow Asgore.
Exact same as Undertale, except the events that happen in Pacifist happen in Genocide, and the events that happen in Genocide happen in Pacifist, with a few exceptions and additions to both.
An innocent creature who urges Frisk not to kill anyone. He is very optimistic and believes that every monster can be good. His catchphrase is, "In this world, it's love and be LOVEd!" He is fried to a crisp when Toriel enters the first room, but of course comes back later as usual. In Genocide, after the Asgore fight is over, Flowey takes the six SOULs and attacks Frisk, sad, disappointed, and angry that Frisk decided to kill everyone. Once Flowey is defeated, Asriel appears out of the Six SOULs and acts similar to Chara at the end of Genocide, with the inevitable options being ERASE and Do Not, and a similar outcome. Themes: "ymenE tsroW ruoY", "evoL dna ,elimS ,maerD ,epoH".
The malevolent ex-wife of Asgore who vehemently hates humans. Residing in the RUINs, she attempts to capture any she spots. Theme: "kaerbtraeH".
An evil but self-controlled skeleton who lives in Snowdin. In the Pacifist Route, he condemns the protagonist for not putting them out of their misery, and attacks them. Theme: "ainavolroniM".
A very evil skeleton who uses dirty traps, abandoning his more pathetic ones. In Genocide, he comments that he appreciates the protagonist's distaste for such harmless traps when they walk through. Theme: "dnirgenoB".
A fish monster who, in the Pacifist Route, hunts the protagonist, and is the Royal Executioner- the name for the Head of the Royal Guard.. Once Frisk has successfully pacified Monster Kid and taught him how to be kind, Undyne kills him (unless he is shoved out of the way beforehand) and attacks. When the protagonist refuses to attack Undyne, she becomes Undyne the Loathsome and becomes a very difficult boss. Themes: "noitpurroC fo raepS", "nialliV eurT a tsniagA elttaB".
A diabolical Royal Scientist working for Asgore. She captured Napstablook, the cousin of Mettaton, and held him hostage, demanding that Mettaton be a slave to her in the body she made for him. Unlike Undertale, she has a battle, but doesn't attack, unless during Pacifist. She eventually gets angry and attacks a few times, until Mettaton stops her, giving Frisk a chance to spare Alphys. If Alphys is spared, she kills Napstablook, much to the dismay of Mettaton. In Genocide, she dies in one hit. Theme: "rehsurC epoH".
A ghost in a robot body that Alphys called Mettaton. He betrays Alphys during her battle, giving Frisk a chance to attack Alphys. If spared, Mettaton is furious, and his betrayal of Alphys causes the death of Napstablook. In this situation, he is in the CORE. During his Pacifist battle, he uses his Mettaton NIHIL form. He dies in one hit in this form, though causing a Neutral Route. In Genocide, he becomes Mettaton SLAV, a form created by Alphys for her own pleasure, during which Mettaton uses his combat features that were also added for "kinks". During the Pacifist, he becomes Mettaton DOOM. Themes: "riapseD yb htaeD", "MOOD fo htarW".
A sad King who regrets his decision not to listen to his wife and kill humans. During Genocide, he attacks. During Pacifist, he can simply be spared. Theme: "niatnuoM eht rednU rotatciD".
A loving human who was taken advantage of by the Dreemurr family long ago. At the end of the Pacifist Route, despite their previous bad experiences with monsters, thanks Frisk for their kindness. During Genocide, Chara does not appear.
W.D. Gaster Edit
Gaster was the former Royal Scientist who built the CORE. His alignment is relative; if the reader's view of Undertale Gaster is that he was good, then he is evil. If the reader's view of Undertale Gaster is that he was evil, then he is good.
Seven Human SOULs Edit
- Yellow - Corruption.
- Blue - Shame.
- Aqua - Intolerance.
- Green - Cruelty.
- Orange - Fear.
- Purple - Apathy.
- Red - Spite.