So... is M3: Sono Kuroki Hagane finished or not?
YES, it is finished.
Why?
This is an original anime and all detected relations are finished. Check the release order section for a complete list of relations.
Watching Order (by release date)
Here you have all the anime relations we detected ordered by release date, so you can see the reason for this status in context and also use it as watching order.
The mangas and the non-core contents are excluded by default, but you can enable them by clicking the buttons below:
Synopsis
M3: Sono Kuroki Hagane tells the story of a group of young people who share a mysterious connection to a dark and dangerous dimension called the Lightless Realm.
Years after an initial encounter in this realm, they are reunited to fight monstrous beings called Admonitions that emerge from it, piloting powerful robots known as Vess.
However, their efforts are only a temporary solution as the Lightless Realm continues to encroach upon their own world.
The situation becomes dire when a new and terrifying enemy, the Corpse, appears, possessing a deadly song that threatens to destroy them all.
Struggling against both the external threat of the Admonitions and the internal turmoil caused by the Corpse's song, the group must overcome their personal struggles to save humanity from the encroaching darkness.