This was probably pointed out before but there is something I really enjoy the way Isayama writes his arcs. They all have a main theme covering small ones.
Fall of Shiganshina Arc is where everything began, EMA lost their home when RBA attacked to Shiganshina and snitched to Walled People, in the background Ymir was crying under a sky because she was thankful to get a new chance by devouring Marcel and Historia was forced to change her name and live a different life right after her mother got killed.
Trost Arc is about the causes our characters want to / will fight for. Jean joining Survey Corps to prevent deaths like Marco’s, Mikasa promising how she is not gonna give up and live to remember Eren when all she has is a tiny blade against a titan; Eren, his wish to be free and vengeance, Armin and outside world are the best examples for this.
Female Titan Arc is about loyalty, trust and sacrifice. Erwin make this clear at his speech in ceremony when he asks candidates to dedicate their hearts. He acts honest to them and asks them if they can sacrifice everything, even their lives for this cause.
Clash of Titans Arc is about returning home. Connie, Sasha, Bertolt, Reiner, Hannes were all wishing to return their homes. Mikasa was trying to get her home, aka Eren, back and Ymir was trying to protect her home, aka Historia. When Ymir went with RB, she also acted out of the theme of this arc and we all know how it turned out. Hannes wanted to bring back something that is long gone and he got eaten. We see this quite clear that if you can’t keep moving on, then no mercy will be shown to you.
Uprising Arc is about facing with the dreams and / or lies our characters have hold on to. Eren realizing how wrong he was at Reiss Cave, Historia realizing what actually Rod is, Levi facing with Kenny, Erwin telling us his childhood are the examples I can think of right now. If you can’t let go of the past, like Kenny and Rod; if you can’t face the lies that were told to you, like Traute and Kenny Squad, you are done.
Return to Shiganshina Arc is about letting go. Hange summed this very well at chapter 84. Levi and Erwin, Hitch and Marlowe, Reiner and Bertolt, Historia and Ymir, Hange and well, so many… Every one of our characters have faced with the danger of something that is precious to them and many lost it.
Since our new arc, Truth of Marley, is quite new, it’s main themes are not quite clear yet. Maybe it is about the realization of how there is no good or bad sides in a war. We’ll see about that one.
I really love when Isa does this. Yes, he is not the best writer out there but he knows his story best. Even when he was a beginner, he has chosen what he wants to teach us through his story. I am really thankful to him.