A YandereSim x Corpse Party Crossover. Or CorpseSick as some people call it.
Summary: After another failed attempt to summon a demon, Oka and her occult club friends decide to test out a charm called the Sachiko-Ever After Charm. But little do they know what horrors they will face!! Will Oka and the other five members survive? Or will they become the next victims of Heavenly Host Elementary Academy?
What if Corpse Party never happened? What if the regular cast gone to Heavenly Host Elementary with their kids? The protagonist, Anna Mochida wakes up to find herself in Heavenly Host Elementary. She and the others have to find a way back to their world and deal with the deaths of their friends.