WARNING: The following contains spoilers for Attack on Titan Season 4, now streaming on Funimation, Hulu and Crunchyroll.
Attack on Titan's Eren Jaeger has changed immensely over the course of the series. Once a naïve and headstrong soldier, he has become a mass murderer and terrorist to both his enemies and his home country. Amidst the carnage, one moment stands out as a sign of this complete upheaval of his character -- his reaction to Sasha's death. The boy who once cared so deeply for the fate of his comrades can do nothing but laugh during one of his dearest friends' demise. But rather than being the callous response of a heartless killer, there may be a deeper, more sinister reason behind his response to her final words.
When Sasha was killed aboard the airship following Paradis' raid on Marley, the final word that left her mouth was "meat." These fitting last words from the squadron's lovable glutton brought almost everybody present to tears. Eren, on the other hand, began chuckling upon hearing the news. Internally, he seems to have realized that Sasha remained true to herself to the very end, as Connie's report triggered a memory of Sasha smuggling meat from their superiors. Nevertheless, like Jean and Connie, many fans were aghast to see Eren finding humor in the moment.
While it's easy to view Eren as uncaring in this moment, this is not the first time he has reacted in such a way to the death of someone dear to him. When Hannes gave his life back in Season 2 during a showdown against the smiling Titan who ate Eren's mother, Eren was so overcome by his emotions that he could do nothing but laugh uncontrollably in between sobbing and berating himself. Just like with Hannes' death, the stress, trauma and guilt of losing Sasha may have caused his emotional stability to snap, especially since it was his plan to attack Marley that caused it. Rather than being amused during her death, his chortling may be a sign of how deeply it hurt him.
Still, there is another possible explanation behind his laughter that may foreshadow even greater tragedy ahead. Before Eren's father Grisha came to Paradis, the previous holder of the Attack Titan, Eren Kruger, explained how all Eldians, whether past, present or future, are connected through cosmic Paths that connect to the Founding Titan. Eren's comrade Ymir glimpsed these Paths after she became the Jaw Titan, as did Zeke in Season 4, Episode 1 while he was being reconstructed by a mysterious girl, although neither knew the significance of them at the time. That being said, neither possessed the Founding Titan, making it impossible for either to unlock its full potential.
Among their many abilities, Titan Shifters have been shown capable of inheriting the memories of their predecessors. The Founding Titan, when paired or in physical contact with a member of the royal bloodline, can access some means of connecting all Eldians. It uses this to alter their memories, personalities and even biology. In Season 4's most recent Episode 3, this is proven to be accomplished via the Paths when Zeke and Eren make contact.
However, Zeke is not the only member of the royal family with whom Eren has made physical contact. Eren first discovered the power of the Coordinate when he punched the smiling Titan, who was later revealed to be Dina Fritz. Additionally, Eren made contact with Historia, previously known as Krista during her time in the Survey Corps, when he kissed her hand at her coronation as the Queen of Paradis. Notably, this is the moment when Eren's friends first observed a shift in his personality.
Since the Paths extend through both the past and future, it may very well be that Eren's encounter with Historia gave him a glimpse of the memories of Eldians from across time. If he looked ahead into events to come, these may have included the moment of Sasha's death. Perhaps Eren had been living in denial up to that moment, thinking that there was a way to make it out with everybody alive. If that were indeed the case, Sasha's death would have confirmed the reality of everything he could have seen in the Paths.
With this in mind, Eren's laughter becomes something much more ominous. It becomes a sign of not only despair at losing Sasha but his resignation to the future. Sasha's death may have been the thing that drove Eren over the edge, forcing him to confront the absurdity of resisting his fate. Should this be true, it would mean he has now accepted his role in whatever lies ahead. Eren would now be committed to bringing about whatever future he saw in the Paths, no matter what atrocities they require of him.
