Attack on Survey Corps

The protagonist and his sister Elsa had to flee their home district of Shiganshina because of an attack by the Colossal and Armored Titan! In the process, they split up with their mother and her fate is unknown... After the disaster, the brother and sister decide to join the Cadet Corps in order to avenge the Titans.  However, the protagonist of the story discovers that quite a few beautif…