Like the popular Attack on Titan, these anime series test the limits of humanity when faced with deadly threats. Attack on Titan is perhaps the one anime that fans credit the most for popularizing the “near-extinction of humanity” trope.
A successful example of this genre is the immensely popular Dr. Stone, where the brilliant Senku keeps on inventing fantastic creations, not just to sustain his Kingdom of Science, but to also bring back all of humanity. Luckily for fans, these aren’t the only 3 anime that explore this fascinating trope.
Humanity creates walls of Varanium, the only known material that repels the virus, and lives behind them. Children who have traces of the virus in their blood are found to be the only effective weapon against these monsters.
Alphonse Elric from Fullmetal Alchemist loses his human body after failing to bring his mother back from the dead. To save Alphonse's life, Alphonse's brother Edward used dangerous alchemy to seal Alphonse's soul into a suit of armor. In his metal form, Alphonse retains his human personality yet loses the ability to feel.
Kaneki Ken from Tokyo Ghoul loses his humanity after an organ from the ghoul Rize is transplanted into his body, which turns him into an artificial half-ghoul. As a ghoul, Kaneki needs to eat humans and other ghouls to survive and prevent bodily deterioration.
Kite from Hunter X Hunter reincarnates into a Chimera Ant after the Royal Guard Neferpitou decapitates and reanimates his original body. Kite awakens in the body of a young girl who ages quicker and gradually remembers his past life.
Tanjiro Kamado from Demon Slayer hunts demons for a living, yet he temporarily transforms into a demon himself after Muzan Kibutsuji poisons him with his blood. As a demon, Tanjiro acquires sharp fangs, slit irises, and fire-like scar markings, along with regenerative abilities.
Palm Siberia from awakens as a Chimera Ant after the Royal Guard captures her and uses her in an experiment to create the perfect Chimera Ant soldier. As part of the experiment, Palm loses the ability to connect her emotions to her memories and becomes hostile, yet regains the ability with Killua's help.
Sakura Minamoto from Zombie Land Saga dies after being hit by a truck until Kotaro Tatsumi resurrects her as a zombie to lead the girl idol group Franchouchou. Sakura initially doubts her leadership capabilities and grows disheartened by her terrible luck. Sakura struggles to recall her human life, yet takes her idol work very seriously.
Mikaela Hyakuya from Seraph of the End sacrifices himself to save his family from subjugation at the hands of vampires, yet transforms into a vampire himself after the vampire Krul Tepes forcibly turns him. Mikaela loses the capacity to feel emotions and struggles to contain his bloodlust, as he continues to hate vampires after joining them.