Enter the Underground, a massive subterranean cave where monsters who once lived harmoniously with humans on the surface have been banished after losing a war with humanity.Enter the Underground, a massive subterranean cave where monsters who once lived harmoniously with humans on the surface have been banished after losing a war with humanity.Enter the Underground, a massive subterranean cave where monsters who once lived harmoniously with humans on the surface have been banished after losing a war with humanity.