Attack on Titan: Crimson Bow and Arrow

For many decades humanity has waged a ceaseless struggle against gigantic creatures that appear without warning and destroy people at every opportunity for contact. To protect the remaining population, enormous walls are erected that completely encircle the inhabited territory, forming a closed system of settlements, military garrisons and farmland. For a century, life inside the fortifications passes without any large-scale invasions, while the defense forces busy themselves with patrols and the training of new soldiers.

Teenager Eren Yeager lives in a border district with his adoptive sister Mikasa Ackerman, watching the everyday life of a town situated along the outer line of defense. Everything changes abruptly when a giant of extraordinary size suddenly appears beside the wall and smashes its upper section with a mighty blow. The resulting breach allows a multitude of the creatures to pour into the populated district, causing mass deaths among the residents and a chaotic evacuation of the survivors. Military units try to organize the defense of the streets while at the same time covering the civilian population's retreat to the inner lines.