In Attack on Titan Season 4, we see Eren capture and eat the host of Warhammer Titan, obtaining it in the process.
Both the Attack on Titan anime and manga make a point of the Warhammer having some impact on Eren. This is done by having one of his pupils focus to a pinpoint, with written heart-thumping onomatopoeia or sound effects playing.
Clearly, Isayama wants to emphasize the Warhammers' effect on Eren here, but exactly what happens to Eren after he eats the Warhammer?
Attack on Titan: What happens to Eren after he eats the Warhammer?
Before and after
In Attack on Titan Season 4’s first episodes, Eren already seemed quite cold, calculating, and committed to the atrocities he must do. While this doesn’t necessarily change after Eren eats the Warhammer, he does seem a bit colder and almost inhuman afterward.
While escaping Marleya, Sasha, unfortunately, dies after being shot by Gabi Braun. Upon being told this, Eren laughs, showing essentially no remorse for Sasha and her death. Eren does flashback to an iconic Sasha moment, but this feels more like an explanation to why Eren is laughing than remorse and mourning.
Eren does then grit his teeth, albeit laughing under his breath still. While Eren may be coming to terms with Sasha’s death, likely, he doesn’t care for Jean or anyone else to lecture him. This is a very different Eren than we saw just a story arc ago when he still cared deeply for his comrades, shown via Armin’s near-death.
Return home
Upon returning to Paradis, Eren is placed in jail as a prisoner due to losing the trust of his Survey Corps comrades. It’s noteworthy that Armin admits he doesn’t know who Eren is anymore immediately after saying he knew him better than anyone, even Mikasa.
Perhaps Isayama further emphasizes the Warhammers effect by choosing to have Armin say it after the Warhammers acquisition.
We see Mikasa then Eren both resolving to fight, Mikasa leaning over a tombstone and Eren slouched over his sink. The symbolic parallel to Mikasa’s similar sentiment while visiting the graves of her friends, whereas Eren is alone in a cell, is significant. Isayama further emphasizes the distance between Eren and his friends by showing how distant Eren is from his family.
Eren then realizes Hange is listening to him after Hange asks who he’s speaking to. Eren reaches through his cell and grabs Hange, violently shaking her around and proclaiming he could escape his cell anytime he wanted. This is highly out of character for Eren’s relationship with Hange, as she’s always been his superior, and Eren has respected that status.
While there are no explicit messages that the Warhammer is changing somehow, connecting the symbolic threads leads to one conclusion. After obtaining the Warhammer Titan, Eren brought about a change, and his friends and family can see this change.
Cutting ties
In the finale of Attack on Titan Season 4, Part 1, we see Eren heavily lean into this disconnect, eventually severing ties altogether. To finalize this severance, Eren escapes his prison cell and forms an extremist group called the Yeagerists. He then teams with Zeke to make all Eldians sterile, eventually making Eldians extinct.
Before totally going rogue, Eren sits down with Armin and Mikasa and has a conversation with them. Eren reassures that he is free and can save Paradis without conflict while torching his relationships with Armin and Mikasa.
Eren essentially degrades them both here, calling Armin soft and not who he once was while being harsher with Mikasa. Eren goes as far as to say he’s always hated Mikasa and that she’s biologically attached to him due to her Ackerman status.
It’s undeniable Eren has drastically changed. Not only is Eren opposing himself directly against his friends, but he’s also going as far as cutting ties with his family. While Eren’s development has shown us different versions of him throughout Attack on Titan, his love for his friends and family was always present.
Somehow, the current Eren doesn’t have that anymore, and the Warhammer is likely the culprit.
Final thoughts
What happens to Eren after eating the Warhammer is nothing short of a total transformation and abandonment of previous ideals.
Attack on Titan Season 4 emphasizes this change and nuances, as seen in the manga via exceptional voice acting and character animation. Attack on Titan has always been about Eren’s journey, so it’s great to see the anime further illustrate how Eren changes after eating the Warhammer.