At the beginning of Attack On Titan, Eren Jaeger was the heroic protagonist. He joined the Survey Corps, hoping he would eradicate the Titans and avenge his losses. Unfortunately, his story didn't follow the typical upward trajectory of other shonen leads.
Eren did not come from a bad family. His fate, as revealed at the end of Attack on Titan, was the result of a slew of experiences and losses he endured throughout his life.
Updated on April 24th, 2023 by Casey Coates: This list has been updated to reflect CBR's current publishing style.
12 Eren Has Always Been Reckless & Violent
Eren's reckless personality and disregard for everyone around him was a red flag from the start. Despite the obvious collateral damage, he didn't see Erwin's plan for him to fight the Female Titan in Stohess District as a problem.
When Eren Jeager and Mikasa were younger, he killed her kidnappers and encouraged her to indulge in the same violence. Though this was to defend someone else, it's still concerning that Eren was so willing to turn to violence at a young age. Retrospectively, it points to him becoming a violent antagonist by the end of Attack on Titan.
11 Eren Declared that he Would Destroy the World
Back in Attack on Titan's first season, Eren lost control when he went into his Titan form. He went berserk and said something pretty concerning. After defeating Annie in Stohess, Eren kept punching her. Since she was already unconscious, it was overkill. Everyone was trying to get through to Eren and tell him to back off.
Eren, on the other hand, was already drunk on power at that point. He was ecstatic from the amount of violence he was committing and didn't want to stop. "I'll destroy the entire world!" he declared at that point.
10 Eren has Always Despised the Titans
Even before Wall Maria was breached, Eren always dreamed of freedom. He felt imprisoned inside the walls and knew the only way to obtain freedom would be to kill the Titans. This desire was only increased after Wall Maria fell and a Titan ate his mother right in front of him.
Initially, this pushed Eren to join the Survey Corps and become a hero. Unfortunately, it led him down a darker path later on. After discovering that he's a Titan Shifter himself, it changed his perspective on things. After discovering that most mindless Titans were former humans, he realized that everything isn't always what it seems.
9 The Death of His Mother Sparked a Fire in Him
After the raging Colossal Titan broke into Shiganshina, hundreds of Titans entered the walls. They indiscriminately killed and consumed many innocent civilians. Eren's mother, Carla, died right in front of him. He and Mikasa tried saving her, but she insisted that they run away and sacrificed herself. Hannes forcibly removed them from the scene, but Eren kept looking back and saw his mother get eaten alive by Dina.
Interestingly, it was revealed at the end of the manga that Eren was also responsible for Carla's death. A future version of himself used the Founding Titan's powers to get Dina to eat her.
8 Eren's Perspective Has Shifted Since Becoming A Titan
Initially, the audience was led to believe that the Titans were the only villains that the heroes would face in Attack on Titan. However, things grew more complicated with the addition of Titan Shifters. Eren becoming one himself suddenly changed his perspective on the world.
Eren inherited the Founding and Attack Titans from Grisha. He didn't know that he ate his own father, either. After leaving the Cadet Corps, he discovered the true potential of his Titan powers. He originally used them to help the Survey Corps, but eventually used them for much more sinister reasons following the time skip.
7 Deaths of His Friends Hardened Eren
Witnessing his mother's death was traumatic enough, but seeing countless allies die in front of him was a major factor in Eren's fall to the dark side. Several of his friends died when the Titans invaded Trost. Then, he joined Levi's squad and felt guilty for his comrades' deaths during their battle against the Female Titan.
The more friends he lost, the darker Eren's mindset became. The audience and main heroes were equally as disturbed when Eren started laughing over Sasha's final words. In some ways, it hardened him to the ways of the world. In other ways, it contributed to the turmoil that drove him to start the Rumbling.
6 After Discovering that His Friends Were Titans, Eren Felt Betrayed
Though Eren lost many of his friends in battle, three of them died for entirely different reasons. When he discovered that Reiner, Bertholdt, and Annie were his enemies, he felt betrayed. Annie was known as the Female Titan. Reiner was known as the Armored Titan. Bertholdt was the Colossal Titan who destroyed Shiganshina by destroying Wall Maria.
They weren't the best of friends, but they did train together. They had a sense of camaraderie that ordinary acquaintances don't have. As a result, it's understandable that Eren was taken aback and hurt by their true identities. It's understandable why it caused him to lose even more faith in the world.
5 Eren was Shaken by Learning What Lay Outside the Walls
Eren had always been curious about the contents of his childhood home's basement. He headed to the basement with a few other Corps members following the second battle for Shiganshina. He opened it with his father's key and was disappointed by what he saw. Titans, in his opinion, pose the greatest danger to humanity.
It turned out, however, that the people outside the walls hated Eldians because of the deeds of King Fritz thousands of years ago. As retaliation for the atrocities committed by their ancestors, the entire world wanted the Eldians eliminated.
4 Getting A Glimpse Of The Future Terrified Eren
Eren was able to predict the future when he touched Historia's hand because she is of royal descent and he is the heir to the Founding Titan. After seeing the monster he would develop into in a few years, he was terrified. He was aware that he couldn't stop it. This was one of the main things that led to Eren's failure.
Eren hated the person he saw in the future and frantically searched for a different answer. Unfortunately, Eren's story could only come to an end by making him the world's worst enemy, according to the red strings of fate.
3 Eren No Longer Has Hope For A Peaceful Resolution
Eren didn't want to accept the future he saw after touching Historia's hand. Despite his desperation, Eren eventually lost faith in a peaceful solution. He left the walls with a few other scouts. They went to the edge of the island where they finally saw the sea that Armin had always talked about as a child.
Most of the scouts seemed hopeful about what lay beyond the walls. However, Eren ominously pointed out into the distance and asked if they'd finally be free after killing everyone on the other side of the ocean.
2 Eren Was Guided Toward Darkness by the Anti-Marleyan Volunteers
When the Anti-Marleyan volunteers arrived in Paradis, everyone was skeptical about working with them at first. They refused to let Eren anywhere near them. However, Eren and Yelena eventually met, bringing the former closer to Zeke.
Eren pretended to agree with their euthanasia plan. However, he and Floch secretly teamed up to form the Jaegerists, overthrow Paradis, and start the Rumbling. Even though it wasn't the Anti-Marleyan's intentions, they enabled Eren's eventual plunge into villainhood. He turned his back on the Survey Corps and was deadset on tearing everything apart.
1 Eren and Zeke Collaborated
Eren met with Zeke in private when he went to Marley alone. In order to trick him, he pretended to be a loving brother. He pretended to support Zeke's intention to prevent the birth of Eldians, and Zeke fell for it.
When they finally arrived at the coordinate, Eren was able to start the Rumbling because of this. Zeke could have accomplished everything he worked for and Eren wouldn't have killed 80% of the world's population if he had exercised more caution around him.