Small story I come up and get request it for no reason and to have fun

A huge thanks to @CerlineRyuu for an amazing cover As the world of undertale and underswap are crossing over and a mysterious power is turning the "heroes" into blood hungry phychopath working together and they only people that can stop it is the Multi-Verse Helping Agency and there agent 013 but will that be enough to stop the "heroes" with genocide intent.