Philosophically, there’s really not a lot going on with Shingeki no Kyojin. Power corrupts; power is inhuman; the strong eat the weak. Anyone who has taken more than a few minutes to observe how society works has probably come to these conclusions.
Rather than make SnK boring, though, in some sense this clears the field for the story to proceed unhindered. It establishes a clear philosophy, so that even though there are narrative and plot surprises each week – often leading to people getting eaten in new and exciting ways – the fundamental “type” of story does not surprise us.
Mikasa fanart by Tsuchinoe Tatsuya
In terms of personality, characters are relatively uncomplicated: you have your good old boys, your grizzled veterans, your crazy ass scientist, your zealots and politicians. Each one has a backstory and a reason for thinking the way that they do. If anyone can be said to be one-dimensional, it’s Mikasa, the talented, traumatized, yet endearing girl whose main goal in life is to be with her adoptive brother Eren. And yet her one-dimensionality is not necessarily the result of sloppy writing or an unwillingness to flesh out the author’s world; it is, rather, the only way she understands how to deal with the pressures of the insane world she lives in.
The titans themselves, though they start out as little more than fleshy murder-bots, are soon differentiated; some are mindless killing machines and some have very complex motivations. The female titan’s story in particular is fascinating, especially regarding the tradeoffs of what power does for you and what it requires you to do for it. But for a few strange decisions, it might even be argued that hers is the most human story of all.
Ultimately Shingeki no Kyojin is a very Greek drama: mortal man is beset by all kinds of forces completely beyond his control, and can only make the best choices he can. Even then, his nature obligates him to make certain choices, so it’s dubious whether he can control his life or not. Calamity and salvation ride on a toss of the dice, and heroic sacrifices are demanded not at rare occasions, but almost daily. It is an excellent reminder of what the world is like for the majority of humanity, even though the plush chairs and Lay-Z-boys the viewers sit in may not invoke that.