Attack on Titan: Chronicle

The anime tells of the struggle between humans and enormous Titans. It all began when gigantic beings appeared on Earth, hostile toward people, destroying their homes and seizing their lands. To survive, humanity gathered in a single city, where mighty fortifications and a sturdy wall were erected to protect it from the Titans' attacks. Even so, the giants keep up their assaults and gradually wear down the defenses, leaving people anxious about the future.

The protagonist, Eren Yeager, and his adoptive sister Mikasa witnessed with their own eyes the attack of a Titan that killed their parents. Afterward the boy vows to exterminate the giants, and together with Mikasa he enlists in a special unit where he is trained in all the combat skills he needs. Some time later, the hero has become an entirely different young man, one who fights Titans and is ready to do anything for humanity's victory. Journeying alongside his adoptive sister, he makes difficult decisions and battles both humans and Titans, finding himself in all kinds of situations along the way.