This post contains major spoilers for the original Neon Genesis Evangelion series.
Neon Genesis Evangelion is on Netflix! That's great! Now there's a whole new generation of anime fans to be awed, emotionally destroyed, and generally perplexed by one of the most influential series ever made. Evangelion starts off as a pretty straightforward, fun mecha anime about giant robots piloted by 14-year-olds fighting off huge beasts that appear out of nowhere to ravage humanity… and then it becomes something else entirely.
About halfway through the season (episode 16, to be precise), Evangelion starts to become less of a shoot-em-up, robots-versus-monsters series and more of an enigmatic character study. Everyone's faults -- like Asuka's fragile self-confidence and traumatic childhood, Rei's crippling lack of ego, and Shinji's belief that he doesn't matter unless he's piloting Unit-01, along with an Oedipus complex -- come to the fore and dominate the rest of the series until the last two episodes, when everything gets really, really weird.
In Episode 24, Kaworu Nagisa waltzes late into the series, posing as the fifth EVA pilot, and quickly befriends Shinji, only to be revealed as the Seventeenth Angel, here to initiate the Third Impact. He travels down to Terminal Dogma to unite himself with what he believes is Adam, the progenitor of all the angels Shinji and co. has been fighting, only to discover that the being NERV has nailed to a cross down there is actually Lilith, the source of humanity. (In Evangelion, neither can exist at the same time; one species can thrive on earth at a time.) After Shinji, piloting Unit-01, defeats Unit-02, which Kaworu was using to defend himself, Kaworu requests that Shinji kill him. He does.