WARNING: The following contains spoilers for Season 4 of Attack on Titan, now streaming on Crunchyroll, Funimation, Hulu and Amazon Prime.
It can be argued that Attack on Titan skirts the line between shonen and seinen. But at its core, it has the heart of a seinen series: Love, hope and the power of friendship usually fail horribly in the face of stiff opposition, and the heroes don't win just because they're the heroes. In Season 4, Attack on Titan's seinen side seems to be taking over.
Although dark, the series' first three seasons behaved more like shonen, wherein hero Eren Yeager fought bitterly as an underdog who just wanted to save lives and make the world a better place. Shonen is often defined by its lead characters striving to be the best. Attack on Titan was a gritty shonen story, but now, Eren's personal arc is steering both him and the story in entirely new directions. The shonen genre is being ushered out. Now, it's all about its characters being the least worst.
Eren Yeager: A Force Of Change, Not Hope
Eren Yeager began the story with a "hidden inner monster" power: the ability to become the Attack Titan or even the Founding Titan. He is one of several Titan Shifters, and at first, Eren sought to save "the last of humanity" with these powers -- even at the risk of his own life. He fought nobly for the sake of others, ready to lay down his life if the walled city could survive in peace. But the revelation of the Titans' true nature, the history of the Eldian people and the Marley Empire completely upended that paradigm. And Eren's goals and methods radically changed.
Eren is no longer a hero of the walled city. He is now a radical Eldian nationalist of sorts, seeking to restore the fallen Eldian Empire that his father Grisha and half-brother Zeke dream of returning to glory. What is more, Eren has become a sort of third party alongside the Paradis Island military and the Marley Empire, being hostile to both. Eren disapproves of Dot Pyxis' cautious, by-the-book methods. He's all about action and results with zero red tape.
Indeed, his raid on Liberio was reckless and devastating, even costing Sasha Braus her life. Eren cared nothing for the casualties and emotional toll; he got what he wanted, such as the deaths of many Tybur and Marley leaders, and the powers of the War Hammer Titan. Eren values power more than honor or authority, which is more how a villain thinks than a hero.
When Eren Goes From Relatable To Grim Spectacle
This is not to say that Eren has failed to remain compelling as Attack on Titan's protagonist. He is more exciting than ever to watch, but the reason is different. At first, Eren was fascinating as the gritty underdog who had lost everything and sought noble revenge, but now his goals, methods and outlook are all different. With his sympathetic edge gone, he has practically been reset as a character. Instead, he is an awe-inspiring instrument of chaos and change, a true driving force for Attack on Titan's plot.
Now, Eren is compelling not because of how he feels or how he's suffered, but because of his bold, world-shaking actions and ideas. He is a spectacle, a wild circus that fuels the viewer's adrenaline. After all, a story's protagonist doesn't have to be heroic or sympathetic in the traditional sense. 'Protagonist' simply means that the audience explores the story and world through that character's eyes, and he or she gets more screen time than anyone else (among other implications).
It's not just Eren himself either -- other characters are also riveting for their bold actions and ideas rather than their sympathetic side. The minor character Kaya, a girl who flew into a rage when she zeroed in on Gabi as Sasha's killer, embodies this. Levi Ackerman has skirted the line between sympathetic and monster all along, being noble but brutal at the same time. It might be said that now, in Season 4, everyone is Levi. Now that's exciting (and scary).