The villains on Attack on Titan are not always villainous, per se, because everyone in the story is fighting for what they believe to be right — excluding, of course, a few who would rather hoard resources and security and leave the unprivileged to choose between starvation and being eaten alive.
The major antagonists in the series act out of self-preservation for the most part, but they have proven themselves to be no less "heroic" than the protagonists on several occasions. In fact, there are times when the villains are actually a lot more human and charitable. But the series' antagonists have still proven themselves capable of despicable acts.
10 Pieck Saves Zeke From Levi's Wrath
Erwin and a small band of Scouts are killed in the process of providing Captain Levi a much-needed diversion as the latter makes his way towards his target unseen. The resulting battle ends with the Beast Titan torn to shreds and Zeke Yeager pulled out of his own hairy corpse.
However, before Levi can capture him, Pieck bursts out of nowhere and rescues Zeke. Levi gives chase, furiously demanding that the Cart Titan return with his prey, but to no avail. Pieck follows what her honor tells her, but snatching closure away from poor Levi is quite upsetting.
9 Reiner Chooses A Gruesome Fate For Marco Bott
During the Trost invasion, Marco Bott unfortunately overhears a conversation between Bertholdt and Reiner, who are discussing their roles as the Colossus and Armored Titans, respectively.
While the Warriors are aware that they cannot set the eavesdropper free, the method of execution Reiner chooses is unnecessarily gruesome. Instead of a merciful and quick death, Marco is deprived of his ODM gear, the only means of escape in his situation — which consequently allows a stray Titan to devour him.
8 Kenny Ackerman Pits Eren And Historia Against Each Other
Kenny Ackerman is also known as Kenny the Ripper, indicating that he cares little about the consequences of his bloodlust, let alone all the corpses he leaves in his wake.
He finds the most bizarre concepts to be amusing. During the tense stand-off between Historia, Rod, and Eren, Kenny suggests that it would be "fun" to watch Eren and Historia duke it out for the Founding Titan. He might be a cold-blooded killer, but forcing two children to kill each other, especially when the ramifications of the battle extend far beyond Paradis, is horrific.
7 Rod Reiss Tries To Force The Founding Titan On Historia
Rod's acceptance of his daughter's legitimacy notwithstanding, the fact remains that he practically orders her to render her royal destiny by absorbing the Founding Titan and restoring blissful ignorance to the people of Paradis.
In addition to this unreasonable demand, Rod insists that Historia kill and eat Eren, her friend and comrade, in order to transfer the Founding Titan to herself. She obviously rejects his expectations on grounds of basic decency, not to mention exposing herself to Mikasa's fury.
6 Floch Forster Helps In The Creation Of The Yeagerists
Floch sets up a meeting between Eren and Yelena, after which Eren states that he plans to destroy the world with the Rumbling. Floch gleefully accepts the proposal, immediately embarking on a quest to accrue support from other people, including members of the Scout Regiment, and ultimately creating the Yeagerists.
While rebel factions often expose the problems with the larger movement they spring from, this group is hellbent on ensuring the end of humanity. Floch's brainchild proves to be a major thorn in the side of the Global Alliance.
5 Zeke Is Responsible For Erwin's Death
Zeke Yeager's weirdly charming human persona is in stark contrast with his actions as the Beast Titan. He murders dozens of soldiers and civilians with his baseball "pitches" — a whirlwind of high-speed rocks that tear his opponents to pieces.
However, his worst crime is killing Commander Erwin Smith during the Battle of Shiganshina. Zeke may have deprived the Scouts of their beloved leader, but this crime haunts him until the day he dies. Levi makes sure of that.
4 Eren Sparks A Global Genocide Of Incalculable Proportions
Eren's devolution from spirited protagonist to clueless antagonist takes several arcs to reach completion, and he gets progressively worse with every stage.
Nothing as awful as his final decision, though: flattening most of the world into a carrion-covered wasteland as payment for their perceived sins against Eldians. Eren's Rumbling is not only unjustified, but also signifies the terror people can unleash on humanity if they have the power to do so.
3 Gabi Regularly Acts On Her Bigoted Convictions
The government of Marley ensures that its Eldian citizens live a second-class life, but what's worse is that they have been indoctrinated with centuries of self-hatred. Such an attempt at brainwashing seems flimsy to those outside the Marleyan sphere of influence, but it has a profound impact on many Eldians.
Gabi takes her convictions beyond the limits of acceptability, however, wildly accusing the people of Paradis of being sinners and trying to attack them for no reason whatsoever. It's seriously a good thing for the Scouts that she switches sides.
2 Annie Obliterates Levi's Special Operations Squad
Annie might claim to be following orders given to her as a Marleyan Warrior, but there is absolutely no reason to toy with her prey in such a violent manner, spinning them to death like a macabre yo-yo.
As the Female Titan, her worst crime occurs against the Special Operations Squad that serves Captain Levi. She murders each of them, one after another, in the hopes that Eren would lose his composure and face her head-on. Annie's tactic is successful, but she has zero moral standing at this point.
1 The First Eldian King Has No Redeeming Qualities Whatsoever
As villains in Attack on Titan go, King Fritz is a violent, hedonistic, and purely self-centered man, thinking of little other than how to expand his empire and obtain eternal glory for himself and his descendants. He compels Ymir to ravage the lands around his tribe and conquer the kingdoms therein. Of course, Fritz gives no credit to his "wife" whatsoever, instead offering her his "seed" as compensation for her efforts.
The man bears no semblance of dignity befitting his position; after Ymir sacrifices herself for him, he makes their daughters Maria, Rose, and Sheena eat their dissected mother raw. The one good thing about the story's ending is that Ymir is freed from her emotional bond to him, which consequently erases Fritz's influence over the world forever.