World System Apocalypse

Every adult in the world has disappeared with monsters replacing them. The strength of humanity's children is fragile - and about to be tested as never before. William is caught up in the disaster with three of his classmates. Friends and family are gone. The system provides new power to the survivors. Monsters invade. In the darkest hour when all hope is nearly lost, new heroes will rise...but at what cost?

Prompt: Survivor Slaughter
Theme(s): #Doomsday
My themes: #Fantasy #Shounen #Apocalyptic