DemonHunterTale is an Undertale AU created by j.zero or jessica-zero. In this AU, the war between humans and monsters happened in 20xx. A demon like being rose in the midst of battle and destroyed half of the world and most of humanity. The monsters and the remaining humans fled into the underground. King Asgore and Queen Toriel with the aid human magic created a barrier that seal the entrances to the underground so that most demons can't enter their last haven. Unfortunately, some demons still managed to slip inside. It was the job of the demon hunters to hunt the demons. There were only a handful of them since killing demons still gave the demon hunters exp this led the demon hunters to be feared and respected at the same time.
They were found by Sans at the age of 8 and have been living with the skeleton brothers ever since. They're good at cooking but somehow can't make edible pasta (Papyrus may be at fault here).
The first son of W.D. Gaster and the older brother of the head of the Royal Guard, the Great Papyrus. He would do anything to not do his work.