NOTE - Although I recommend reading my anthology story "Depths of The UnderVerse" first, explanations will be in place where this story can be read on its own, separate of the anthology story I have written, so don't worry too much about it if you're reading this one first... Sure, Some lore won't make sense at first...
Among the infinite Underverse there was a Dust Sans variant. He had the special ability to hop universes, and he used this to go around the different worlds, causing pain and suffering. However, one day he decided just simple killing wasn't enough anymore... He wanted something bigger, he didn't want to just kill them...
Error and Ink live outside of it all... Each keeping an eye on the timeline, for different purposes... But every now and then... There's a couple of AUs that catch their eyes, something out of the ordinary... Something... Odd... Either something downright strange, or something horrifying.. Usually there's your UnderSw...