M3 ~ソノ黒キ鋼~

M3 the dark metal is a 2014 Japanese anime television series produced by Satelight. It is directed by Junichi Sato, written by Mari Okada and features mecha designs by Shōji Kawamori. The story revolves around a group of children who meet and bond in a dark void known as the Lightless Realm, but are then separated and returned to their own dimensions. Years later, these children reunite to fight "Admonitions," monsters that originate from the same void, using robots known as "Vess." However, their efforts only slow the ever-encroaching and expanding Lightless Realm from infecting their world. Their lives take a drastic turn when a new foe appears in the form of a "Corpse," whose song is rumored to kill any who hear it within nine days. The group hears the "Corpse Song," and with this, they each begin to pull away and become caught up in their own personal problems—ultimately threatening the fate of humanity. The anime aired from April 21, 2014, to October 1, 2014, and was available for online simulcast streaming worldwide (excluding Japan and China) by Daisuki.