Attack On Titan Vol. 23

In a world where humanity has been pushed to the brink of extinction by a terrifying race of man-eating giants known as Titans, the towering city walls that had kept humans safe for over 100 years are suddenly breached by a single Colossal Titan of unimaginable size.
The intense trauma of witnessing his own mother being devoured by a Titan gives birth to an unlikely young hero, Eren Yeager, who solemnly vows to slaughter every last Titan on Earth. Together with his adopted sister Mikasa and best friend Armin, they join the military and train to join the most elite group of Titan-slayers, and, along the way, discover the unknown mysteries regarding the Titan and human races…
After the battle against the Beast Titan, Eren and his group have somehow made it to the basement. They learn about Grisha’s upbringing and reasons for coming inside the wall, as well as who their real enemy is: bigger than a Titan, it’s the world itself. Learning that there’s no freedom beyond the walls, and that an enemy waits towards the sea, Eren and the others have one place to go in volume 23.
Notice: This manga is written in Japanese.