Excellent post. It does a great job of summarising the parallels between Griffith and Guts' psyches up to this point in time. What I found most interesting were the pictures that relate to each man's relationship with Casca.
The images of Griffith actually raping Casca and of Guts almost(?) raping her seem, on the surface, to be about each man's relationship to her, and on one level they are. But in a more significant way it is also about their relationship with each other. While the images with Casca show the similarities between Guts and Griffith's alter ego's, when you put them back into context they also show the power struggle that is taking place between the two. Casca is merely one battlefield in this continuing struggle that has been taking place for a long time.
Rape often has more to do with power than it does sex. Two events took Griffith's power from him. Guts defeating him in a duel (and then subsequently leaving him), and the year Griffith spent being tortured. The first took his pride and his confidence, while the second took his material assets, i.e. his status in the world and his body. Griffith blamed Guts for the loss of his dream, and the fact that he then took Casca too (whom Giffith felt also belonged to him) must have been a double blow.
Now, when Griffith raped Casca he was not only displaying his power over her, but over Guts too. He was basically saying "Look what I can do to your girl" while Guts lay there helpless. He was, in effect, taking his power back from Guts and re-asserting his dominance over his (former) comrade. Of course the rape wasn't all Griffith, his new demonic nature took the step that he may never have taken, but there is no doubting that Griffith desired to get back at Guts and take back what he felt was rightfully his.
Now lets look at the relationhip from Guts' perspective. Ever since Griffith's speech about how a friend is someone who is "equal" to him, Guts has carried around a feeling of inferiority towards his best friend. Up until this point, I think that Guts felt the two were equals, or "comrades in arms" (despite the fact that Griffith outranked Guts). But Griffiths words shattered that illusion. Guts desire to pursue his own dream was initiated by his desire to earn the respect of his friend and reclaim his lost pride, which Griffith had unknowingly taken away. I think it's fair to say that Guts never felt the same way about Griffith again, and that the struggle between them began at that moment.
After the eclipse, Guts was in the position Griffith was in during his year in torture. Guts was the one who had lost everything, his friends (though he had abandoned them once anyway), his love, and his pride. And now, obviously, he wants to get back on level terms. Guts' "revenge" is more about his own hurt pride than avenging the Hawks or what was done to Casca. Which makes our hero seem more immature than we, as the audience would like him to be, but I think thats the reality of the situation.
Now, perhaps the most interesting point is that, as Griff pointed out with his pic, Guts was emulating Griffith when he (almost) raped Casca. On the surface, this was caused by his feelings of anger, frustration and pain from what he had gone through over the past three years. But I feel that subconsciously, this was another round of the struggle between Griffith and himself. Remember, when Griffith raped Casca, he was, in a manner of speaking, taking her from Guts. To Guts, it wasn't so much the fact that he had lost Casca, but that Griffith had taken his girl, his possession. Griffith had taken something from him - and he was going to take it back. It had nothing to do with his frustrations, pain or love for Casca, but his need to get even with Griffith.
But what about Casca? Well sadly for her, she, as I mentioned earlier is just another factor in their continual struggle. She could quite easily be replaced by something else, but we all know that a woman caught between two men makes for a great plot device! ;D. When I first came to the conclusion that Casca's place was merely as an object in a struggle between two other people my empathy for her grew ten fold. I mean, it's bad enough being raped by the two men you love, but it wasn't even about her, it was about them getting back at each other. I'm sure (well I hope) there is a bright ending for Casca, but I think she needs to first free herself emotionally from the two men she loves, and live for herself.
Well that was a long rant! Sorry for going off on a tangent, and I suspect that many of you have already come to some similar conclusions, but for some reason the pics posted by Griff gave me the sudden urge to write some of my own thoughts down. At the very least it gave me something to chew over for a while. ;D