"My War/ Boku no Sensou" by Shinsei Kamattechan is the first opening of season four, and it brings a completely different kind of energy to Attack on Titan. Though some viewers were not big fans of it at first because it wasn't what was expected of an Attack on Titan opening. Attack on Titan has been known for its epic openings, jam-packed with excitable fight scenes, and hints at the arc that season is exploring. The first opening, "Guren no Yumiya" by Linked Horizon, ruled the internet in 2013 with hundreds of videos using the song in order to convey heroic battles and intense situations. Their other opening, "Shinzou wo Sasageyo", is the national anthem for all anime watchers.
So when season four came out, everyone expected something along the same lines: an epic, powerhouse of an opening to get ready for the grand finale of one of the most popular anime of all time. "My War" doesn't focus on sequences of 3DMG to rock music. It doesn't even meld with "Red Swan" and provide character study in place of action scenes. It displays scenes in grayscale interrupted by explosions of color. None of the characters are present except for a statue of Eren's Attack Titan at the very end. "My War" invokes themes of war and death without any of the usual Attack on Titan flare, and it works perfectly.
Colors in "My War"
Season four of Attack on Titan has shown a drastic change from what fans have expected from the series. With the bombshell of a plot twist at the end of season three, the truth that humanity is not on the verge of extinction at all, many audience members went into season four not knowing what to expect. There was suddenly a gray area in a show that had originally been so clear-cut: titans are bad and humans are good. You can't win if you don't fight.
The plot twist did its job of unbalancing the viewer, leaving people reeling over the direction the show would take. The rhythm was continuously thrown off when season four started not with Eren, Mikasa, and Armin, but with a group of Marleyian children, the audience had never seen before. All these changes and unfamiliarity are is perfectly summed up in the opening. Everything that was once familiar has been changed, and there is no way to go back to how things were before.
Destruction
Not having any focus on a particular character only adds to this alienation, but there is a focus on Eren's current distance from the rest of his friends. Without a spotlight on Mikasa or Levi doing a cool 3DMG trick, Armin covered in blood, or Eren smashing his fist into the Armored Titan's face, what's left is a noticeable lack of camaraderie. Eren is pulling away from his friends, and so that fellowship is no longer present, just another jarring change to the opening.
However, one of the biggest changes is the lack of titans. There are glimpses of a titan statue, of maybe a shifter transforming in a rush of color and steam, but that's about it. "My War" hinges more on human violence: bombs, guns, flamethrowers, and explosions. Some scenes of battle are even repeated over and over, signifying the repletion of human violence. Titans are no longer the enemy; they were weapons deployed by a different country to kill another.
Eren's Attack Titan Statue
Humanity's self-destruction seems to be a prevalent theme of "My War", and Eren functions as the eyes the audience looks through. As Marleyans and Eldians are destroyed alike, and the body of birds and children rain from the sky, Eren's titan stands solid, reaching out and moving forward. This is Eren's view of the world, and a preview of the destruction the Rumbling will wage. Just as the lyrics state, this is Eren Jaeger's last war.