DystopianTale (Undertale AU)

After the monsters win the monster/human war, most humans are whipped out, monsters taking over. Now, in the year 2113, Frisk and Chara are two of the few humans left in BlightView: one of the monster capital of the world, ruled over by King W.D Gaster, with his adoptive son, Dream, by his side. But like anything, the Castle holds many dark secrets of its own...

And of course, nothing is as it seems in the city as well, as it is that most people who don't live in or near the city centre have it extremely rough, all being treated roughly and unfairly, living in poor conditions. A rebellion is soon formed in the "slums", the outskirts of BlightView, run by Error, along with other misfits, like small, rundown Sans, who lives with a grieving Asgore outside of the city, and an enraged Cross, who wishes for nothing more than revenge, and young Killer, a boy who grew up in the slums without parents and a strange medical condition. The rebellion is the city's last hope.

(Rated M for mature topics, swearing, and graphic/disturbing scenes)