This is a crossover between Percy Jackson and Undertale After a genocide route, Sans is somehow not dead, and Chara has broken the barrier and mysteriously disappeared. Percy and his friends decided to investigate the mysterious explosion site at Mt. Ebott, before Annabeth joins the quest party, she finds a book in a mysterious library that describes the monsters before they were locked in the underground. None of these characters are mine Undertale belongs to Toby Fox Percy Jackson belongs to Rick Riordan This takes place after trials of Apollo so RIP Jason This will probably have made up soul traits and references from other Undertale AUs. All the demigods will have different soul traits, and I will probably make up some soul traits along the way (This might be bad) Maybe Cringe