Eren Jaeger from Attack on Titan wears the protagonist's mantle when starts his journey; however, his actions, attitude, and ambition as an adult fall in the antagonist category. He insists that his decision is the right one, that eradicating Titans (and later the whole world) is the path to salvation.
The manga concludes with an uneasy stalemate between Paradis and everyone else—not to mention, Eren makes good on his promise to keep his friends safe, so perhaps he isn't entirely in the wrong. That said, he fumbles along the way a few too many times for comfort.
10 Eren Accepts The Jaegerists As Essential To His Plan
Floch Forster's maniacal devotion to Eren's vision is a source of conflict within the Scout Regiment, one that the latter inevitably loses when the Jaegerists accrue enough followers to make their stand count.
Although touted as a rebellion against convention, the Jaegerists are actually far from being revolutionary fighters, instead resorting to cheap tactics to instill a sense of fear in their opponents. Eren realizes this in advance, but he chooses to rely on them to satisfy his goals.
9 He Asks Historia To Eat Him And Get It Over With
Eren turns desperate when he learns about Rod Reiss' proposal for him, paradoxically accepting being eaten by Historia as part of his destiny. At this point, his Attack Titan is an important asset for the Scouts, which is why his behavior is shameful and disloyal—to Paradis as much as to himself.
Historia firmly vetoes her father's order, but Eren demands that she follow through because he wants to free himself of the many burdens he carries. He doesn't consider how Armin and Mikasa would feel if this scenario really happened, either.
8 Eren Allows Levi's Core Team To Be Killed For No Reason
Levi and his Special Operations Squad assure Eren that he would be safe with them, a believable claim given that Petral, Oluo, Gunther, and Eld are among the strongest anti-Titan warriors in the Scouts.
Unfortunately, Eren's trust in their abilities inadvertently results in their deaths at the hands of the Female Titan. Rather than maintaining his course, he opts to transform and defeat his enemy, forcing Levi and Mikasa to chase after and rescue him.
7 He Destroys Hundreds Of Innocent Marleyan Lives
At the end of his secret mission in Liberio, Eren's Attack Titan ravages the festival hosted by Willy Tybur, hoping to add more of the Nine Titans to his inventory.
In the process, a vast number of people are killed, including children and the elderly, all to support Eren's bizarre cause. To call this event a failure would be to grossly understate the situation—it's a human rights disaster more than anything else.
6 Eren Sparks The Flames Of Revolution In His Enemies
Eren is aware that being the cause of wanton death and destruction is only going to make his enemies hate him more, but this realization does little to hinder his plans.
The Liberio massacre is directly responsible for Gabi's rage, a single-minded vengeance that leads to Sasha Braus' assassination. By hurting others, Eren is merely adding fuel to the fires of anti-Eldian bigotry that have already been burning for centuries.
5 He Forces His Loved Ones To Clean Up His Mess
Eren blithely ignores the consequences of everything he does, regardless of how many problems he creates for his loved ones. He is confident that they will always be there to back him when required, whether to help him escape or fight on his behalf.
Eren leaves a trail of blood behind him, because of his unwavering certainty that his friends will take care of the "inconsequential" matters that he couldn't be bothered with.
4 Eren Deceives Ymir The Founder Without Truly Acknowledging Her Suffering
Ymir's 17-century-long suffering is of no concern to Eren, as he believes that his ultimate aim would result in her freedom as well. Regardless, the fact that he callously tricks Ymir into authorizing his access to the Founding Titan by reminding her of her misery is downright disgraceful. While Eren technically succeeds in this case, it is an ethical failure of massive proportions.
3 He Openly Declares War On The World
Eren is pro-genocide, a stance he stubbornly reiterates throughout the series. Neither common sense nor common decency is capable of swaying his mind, which in itself is quite revealing.
Eren doesn't expect anyone else to assist him in bringing about mass human extermination, but it makes no difference in the overall scheme of things. Once he announces his intention to sacrifice the world to his whims, there's nowhere to go but down for Eren.
2 Eren Refuses Alternative Paths Towards Peace
Zeke Jaeger offers a significantly kinder alternative to global carnage—by regulating the powers of the Founding Titan in such a way that the Eldian race is eradicated.
This plan doesn't involve any deaths whatsoever, only "sterilizing" Eldian individuals so they will be unable to maintain their population, gradually dying out over the next few decades. Although Zeke's idea is a moral quagmire in its own right, the Rumbling is incalculably worse in every respect.
1 He Is Unable To Save Paradis From Itself
After Eren's death, the world begins to recover from an unprecedented amount of damage, reaching a point of relative balance within three years. A few heroes from the final battle are sent to Paradis to open channels for international discourse, mainly because of the unnerving discovery that the Jaegerists have made a successful grab for power.
This means that Eren's dream of protecting his people is not exactly fulfilled, considering that Paradis is almost on the brink of civil war. The Eldian race might just turn out to be their own worst enemy.