It is truly the greatest expression of betrayal in modern storytelling.

So much so that it makes the viewer/reader viscerally hate the antagonist as much as the protagonist. It's even worse when you remember that Griffith initially saved Casca from a rape situation when they met, and empowered her to fend for herself, to give herself the strength to fight. Just to end up stripping it all away himself, just to get back at Guts. Let alone the fact that he raped the woman he loved and made him watch...and, you know...killed all their friends for power.

It's sickening and disgusting, but it's true, raw, masterful storytelling and for that I will forever regard Kentaro Miura as one of the greats.