M3: Sono Kuroki Hagane

Synopsis

In the depths of the Lightless Realm, a gathering of children forge lasting friendships before being dispersed across different dimensions. Years pass, and these same children come together once more to combat "Admonitions"—beings born from the same void—by piloting robots known as "Vess." Their struggles temporarily halt the encroaching Lightless Realm from overwhelming their world. Their lives take a drastic turn with the emergence of a new adversary, a "Corpse" whose melody is lethal to those who hear it within nine days. Upon hearing this "Corpse Song," each member starts to retreat into their personal struggles, jeopardizing the future of humanity.