Neppuu Kairiku Bushi Road

An asteroid collision brought with it a deadly menace known as "Shinobi." Faced with destruction, humanity retreated to land reclaimed from the sea. The one ray of hope is a device that can fight the Shinbo called "The Mechanical Divine General." Ame, the princess of the refugees, and Suō, who carries the blood of the Yagyū family, must awaken its power in order to save the world.

Synopsis from Anime News Network