About the AU
Endtale is an AU where the Surface has suffered through a war, which has effected the Underground in multiple ways. Frisk enters the Underground after escaping their 'tribe', where a tyrannical leader has taken power. When they enter the Underground, they go through the usual Pacifist/Neutral/Genocide route, and escape the Underground. If they did a Pacifist route, they create a new group with the Monsters when they escape.
The Downfall is the human-given name to the war that citizens of the USA and Iran gave to the war that both countries are locked in. At least, those who weren't drafted. It all started when Qasem Soleimani, an Iranian general, was assassinated, and it all went down from there. Officially, though, things went to hell in 2023, when the first bomb was dropped. That's when things turned from bad, to worse.
-Papyrus, Undyne, Alphys and most of the Royal Guard (minus Greater Dog, Lesser Dog, Doggo and Dogamy), were killed or injured when a group of Mutants fell into the Underground.
-Sans is the Royal Scientist, due to previously holding a similar career.
-Gaster can be seen once in Snowdin, once in Waterfall, and twice in Hotland, due to the fact that he is actively working to bring himself back.
Frisk is a quiet, cautious child, who can find it hard to trust people. They often stay in the Ruins with Toriel, though can be seen in Snowdin or Waterfall. They have only gone to Hotland once, and have never been to New Home. Usually, they are seen in the clothes they fell down with; a green/blue sweater, ripped jeans, and combat boots, along with a walking stick that doubles as a weapon.
Key is one of the surface animals that had fallen, a large husky that lives in Snowdin. They're a playful dog, with light whitish-grey fur and grey eyes. They have a navy blue collar around their neck. Frisk adopts them after they visit Doggo's old sentry post, where Key was hiding.
At first, Flowey will confuse Frisk for one of the many mutants that falls underground, though once he finds out they're a human, he'll stop trying to attack you. He'll go with you throughout the Underground, encouraging you to either kill most monsters you find. In the Final Corridor, after you meet with Sans, he will reveal that he planned to absorb your soul after you fought Asgore. If Frisk went Pacifist or Neutral-Pacifist, he will then tell them about how, with each monster they spared, he hesitated more on the plan, until eventually deciding to help you along the way. If Frisk went Genocidal, a fight with Flowey will start after he revealed his plan. If Flowey wins, he will reset, and if Frisk wins, they will kill Flowey and continue on.
Toriel is often trying to distract herself, unable to deal with the condition the Underground is in. She will, unlike her classic counterpart, leave the Ruins. The reasons she does this will vary. On a Pacifist or Neutral route, she will leave to either check on Frisk, help Sans with his work, or meet with Asgore.
The Royal Guard
The Royal Guard is spread thin across the Underground, with the only living original members being Dogamy, Greater Dog, Lesser Dog and Doggo. Some of the CORE Mercenaries have joined, though they still need more members.
Mettaton is training to become a member of the Royal Guard, though he still does his show to keep the monsters occupied. He is much less theatric, and works with Napstablook on songs to cheer his cousin up. Sometimes, he helps with work on the Core when it would be too dangerous for a normal monster to do so. His NEO form has been upgraded during a Genocide Run in anticipation of fighting the Human.
Sans, the current Royal Scientist, rarely leaves the Lab. He is often working, though he is not sure whether it will amount to anything. On the weekends, he will meet with Toriel at Grillby's, which is when he is most like his classic self. He wears a thin, patched labcoat, a white t-shirt, jeans and black shoes, along with Papyrus's scarf. Sometimes, he will watch some of the old anime tapes from Alphys.
Muffet is a chatty young baker, traveling the Underground in her mobile restaurant. She is hopeful that the barrier will be broken, and will attack Frisk if they hurt a spider. She tries to keep people's spirits up, though it can be pretty hard. She can be seen playing fetch with her spider pet when she isn't working.
Asgore is only seen outside of New Home when buying groceries. He is unable to deal with the deteriorating condition of the Underground, especially since it wasn't that good before. He's almost given up entirely on the 'collect human souls' plan after the mutants fell, though still has some hope left. He doesn't talk much, since he doesn't really see the need for it.