Centuries ago, mankind was slaughtered to near extinction by monstrous humanoid creatures called Titans, forcing humans to hide in fear behind enormous concentric walls. What makes these giants truly terrifying is that their taste for human flesh is not born out of hunger but what appears to be out of pleasure. To ensure their survival, the remnants of humanity began living within defensive barriers, resulting in one hundred years without a single titan encounter. However, that fragile calm is soon shattered when a colossal Titan manages to breach the supposedly impregnable outer wall, reigniting the fight for survival against the man-eating abominations. After witnessing a horrific personal loss at the hands of the invading creatures, Eren Yeager dedicates his life to their eradication by enlisting into the Survey Corps, an elite military unit that combats the merciless humanoids outside the protection of the walls. Eren, his adopted sister Mikasa Ackerman, and his childhood friend Armin Arlert join the brutal war against the Titans and race to discover a way of defeating them before the last walls are breached.

The seemingly unimpressive Saitama has a rather unique hobby: being a hero. In order to pursue his childhood dream, Saitama relentlessly trained for three years, losing all of his hair in the process. Now, Saitama is so powerful, he can defeat any enemy with just one punch. However, having no one capable of matching his strength has led Saitama to an unexpected problem—he is no longer able to enjoy the thrill of battling and has become quite bored. One day, Saitama catches the attention of 19-year-old cyborg Genos, who witnesses his power and wishes to become Saitama's disciple. Genos proposes that the two join the Hero Association in order to become certified heroes that will be recognized for their positive contributions to society. Saitama, who is shocked that no one knows who he is, quickly agrees. Meeting new allies and taking on new foes, Saitama embarks on a new journey as a member of the Hero Association to experience the excitement of battle he once felt.

A sinister threat is invading Tokyo: flesh-eating ghouls who appear identical to humans and blend into their population. Reserved college student Ken Kaneki buries his nose in books and avoids the news of the growing crisis. However, the appearance of an attractive woman named Rize Kamishiro shatters his solitude when she forwardly asks him on a date. While walking Rize home, Kaneki discovers she isn't as kind as she first appeared, and she has led him on with sinister intent. After a tragic struggle, he later awakens in a hospital to learn his life was saved by transplanting the now deceased Rize's organs into his own body. Kaneki's body begins to change in horrifying ways, and he transforms into a human-ghoul hybrid. As he embarks on his new dreadful journey, Kaneki clings to his humanity in the evolving bloody conflict between society's new monsters and the government agents who hunt them.

Still threatened by the Titans that rob them of their freedom, mankind remains caged inside the two remaining walls. Efforts to eradicate these monsters continue; however, threats arise not only from the Titans beyond the walls, but from the humans within them as well. After being rescued from the Colossal and Armored Titans, Eren Yaeger devotes himself to improving his Titan form. Krista Lenz struggles to accept the loss of her friend, Captain Levi chooses Eren and his friends to form his new personal squad, and Commander Erwin Smith recovers from his injuries. All seems well for the soldiers, until the government suddenly demands custody of Eren and Krista. The Survey Corps' recent successes have drawn attention, and a familiar face from Levi's past is sent to collect the wanted soldiers. Sought after by the government, Levi and his new squad must evade their adversaries in hopes of keeping Eren and Krista safe. Eren and his fellow soldiers are not only fighting for their survival against the terrifying Titans, but also against the terror of a far more conniving foe: their fellow humans.