Warning: The following contains major spoilers for the Attack on Titan manga and its conclusion.
Attack on Titan has a global audience as one of the most popular contemporary anime series of all time. The emotional struggle of the main characters and the moral quandaries residing within the battle captures the viewers' hearts. However, now that the manga has ended, people can't help but wonder if the ending could have been better.
Eren Yeager is an unusual protagonist for a shonen manga. The plot twist that changes his entire character to a turnaround is brilliant, and the tragic romance between Eren and Mikasa makes readers wish for a happy ending more than anything else. Now that the manga has ended, the question remains -- is the ending sad or happy?
How Does Eren Die?
Eren has the intention to save the Eldians and everyone he cares about -- but at what cost? He attempts to destroy the world, killing millions in the process to ensure the safety of all Eldians. He wishes for freedom more than anyone else and knows that there's no freedom for Eldians as long as Titans exist. His death is therefore the only means to erase the existence of titans from the world.
During the final moments of the war, Mikasa herself decapacitates Eren. Although she feels torn between her love for Eren and her loyalty to her people, she ultimately chooses the latter. Ever since childhood, Mikasa has been in love with Eren, which means killing him is the most difficult decision she has to make. However, it's something that Eren predicts. Thus, he creates situations where Mikasa has no choice other than to kill him.
Does Eren's Death Result in Peace Between Eldia and Marley?
Eren's death and the disappearance of the titans from the world don't result in world peace immediately. Once Eren dies, the source of titan powers dies with him. Those who are titans turn back into humans. Everyone moves on with their lives, including Armin and Mikasa. Three years later, the world starts to get back on its feet after the devastating war. Eldia forms an army under the Jaeger faction and focuses on strengthening its military forces. There is still a perceived threat among Eldians that the rest of the world will retaliate with even better military forces. The animosity between Marley and Eldia exists for over a millennium until every person from that race is eliminated.
Does Mikasa Move On With Her Life?
Mikasa buries Eren in a place where he loved to take naps. Days pass by and she keeps visiting his grave. The manga only shows the back profile of her relatives, but the panels hint that she marries and starts a family. She also takes her husband and children to Eren's grave site. Even after all those years, she never lets go of the scarf he gave her. Eventually, she dies from old age and is buried while wearing the same scarf. Even after moving on with her life, Mikasa carries Eren's memories with her. Fans speculate that she marries Jean, but this is simply an assumption based on the hairstyle of her husband -- Isayama never clarifies who she ends up with.
What Kind of Ending Does Attack on Titan Have?
It's not entirely possible to categorize AoT's ending as either happy or sad. Eren dies, but everyone moves on with their lives, with him never achieving the freedom he sought his entire life. However, the people around Eren work to create a better world for Eldians. Even Mikasa finds her happiness despite being in love with Eren since their childhood. The ending can perhaps best be described as bittersweet, leaving fans satisfied but with plenty of melancholy.