Knights of Sidonia (2014)

After the obliteration of Earth by the alien Gauna, humanity clings to survival on the spacecraft Sidonia. A century has passed since the last Gauna attack, but enlistment in the military remains compulsory. Nagate Tanikaze emerges from the hidden depths where his grandfather concealed him, stepping into a world he's never known. Just as he begins to navigate this unfamiliar life, the Gauna return, posing a renewed threat and thrusting him into the heart of a desperate fight for survival.