tl;dr KYM Plays Deltarune is a RP that somehow became a Deltarune/Homestuck/Earthbound/Undertale crossover in which people's self inserts go around doing weird shit that I am unable to understand. You should probably ask Olors if you want a more detailed synopsis.
THE STORY THUS FAR:
-Susie, Olors, Omega MISSINGNO, Soup King, and Kris fell into the Dark World
-We fought Lancer, who was stalking Kris
-We found Ralsei
-This guy Mago comes out of a portal
-Kaijin sends this jester named Ludibrium to keep an eye on Mago
-Ludibrium gets banished to another world
-Kaijin and his units become an amalgamate
-MISSINGNO and Ralsei become auspisticized by Olors
-Olors is revealed to be the Muse of Life
-Olors becomes a cherub
-Trolls appear in the Dark World
-The Dark World become super freaky for some reason
-Ralsei and Mago fight Lancer and Susie
-Some girl named Yoki joins the party and uses PK Beam
-A witch named Claire joins the party
idk if olors will actually update this but who knows?