SNK context post for the happy non-initiated:
So, set the stage and suspend your disbelief: Post-Apocalyptic world! Think Western-Europe idealised rural mid 19-th century in terms of technology.
Humanity was doing just fine until GIANT MAN-EATING GIANTS popped up out of nowhere all across the world. Said Giants (the eponymous “Titans”) are virtually unkillable, don’t eat, don’t sleep, and just want to kill humans. Bad news.
Eventually what little that remains of the human population builds a huge Trojan-like wall around their city, and another one around that, and another one around that (with the upper classes in the inner circle and the farmers in the outer circle, you know how this works) and this keeps the Giants out. By the time the story starts, that’s how it’s been for centuries: humanity lives within its relatively tiny, self-built cage and feels safe there, because Outside There Be Monsters. No one wants to go outside anymore -
- EXCEPT for the Scouting Legion/Survey Corps (cue heroic music). One branch of the three-branched Military, they’re tasked with going periodically outside of the Really Big Safety Walls and find out stuff about the Giants, with the eventual goal of maybe defeating them and taking over the rest of the world again. They’re considered suicidal weirdos or heroes, depending on who you ask (and how successful they’ve been lately) and their death rates are through the roof. They also fight the Giant Man-Eating Titans by flying around like Spiderman waving swords while wearing a bondage harness. No, really.
The Legion is led by Commander Erwin Smith, tall athletic blond with good eyebrows. Reasonable Authority Figure, but he’ll also not hesitate for even a second to do some Highly Questionable Things if he thinks it’s for the good of humanity. (As a point of reference, one of the main inspirations for his character was apparently Erwin Rommel.) His second-in-command is Levi, a short grumpy rude traumatised ex-thug who for some reason is extremely good at killing the aforementioned Giants/Titans. Nicknamed the One Man Army, very irritable and brusque, but at heart he just want to save as many people as he can. Deeply devoted to Erwin. He’s also the First Half of the Ship.
Enter our three heroes: Eren, little ball of righteous rage; Mikasa, calm traumatised ball of rage; and Armin: small, physically weak, but terrifyingly smart. They grow up together and go to a collective trauma when the Third Wall is breached and Titans suddenly can come into the outside bits of the city. They’ve got to evacuate everyone to inside the Second Wall. Eren's mother dies and he vows to join the Scouting Legion. Mikasa, protective adoptive sister, follows him in order to protect him. Armin follows too, partly out of friendship but mostly because he’s insanely curious to see what’s outside the walls.
They join up, they train, they get accepted into the Legion. Shit Goes Down. Turns out Eren can transform himself into a Titan for some reason. More shit goes down, they find out humans are behind the Titan attacks, battles are fought, corruption discovered, and somewhere along the road both Erwin and Armin get mortally wounded. Luckily, there’s a Magic Healing Potion! Less luckily, there’s only enough for one. This prompts a long discussion/fight between Eren and Levi, but eventually Levi gives in and tells them to save Armin (who’s already proved himself to be a strategic genius), and says goodbye to Erwin with the words let him rest.
And that’s roughly where the story picks up...