Well, this is where my analysis of Griffith ends. As a Griffith apologist, I don’t expect anyone to condone what he did, but I do hope you could sympathize with why he did it. He did not just flippantly choose to become Femto for the hell of it. This was the most compelling case for turning to the Dark Side that I have ever seen!

There can be no blame here, just a horrific sequence of events that set up an epic tragedy. For this is the path of all fated to the Behelit. First your life gets destroyed in ways specifically tailored to your worst fears, until you are completely broken in mind and/or body. And then, at your absolute lowest point of despair, the God Hand shows up, playing on those weaknesses and offering you a way out. It is explicitly designed to be an offer you can't refuse.

It is the story of a street urchin who, inspired by a beautiful dream, took himself and those who followed him all the way to the top. And just when his dream was within reach, he was torn from it in the cruelest way imaginable. After being mutilated and tortured for a year, he lost not only his reputation, his friends, and his freedom, but also such basic human dignities as talking, walking, and feeding himself. With his sanity hanging by a thread, he even came close to losing himself, but he would not let that happen. I challenge anyone to put themselves in Griffith’s place and say they would not make the same choice a lot faster!

The road to Hell is paved with good intentions. Just as Lucifer was once the most radiant angel in Heaven, so too was Griffith’s rise and fall a result of his enormous pride. It’s not that Griffith didn’t care about others, he just cared about himself more. When it came to Guts, he sometimes cared about himself less.

"A man should envision such a lifetime once. A life spent as a martyr to the god named 'Dream.'" Griffith, Vol. 6 Ch. 6

Griffith's story is important to me, because I relate to his idea of "dreams" very strongly. Who among you have something in your lives that you feel so strongly about, you would do anything for it? Who exist not for your own sake, but as an embodiment of an idea? Whose purity of heart is enough to overcome any obstacle? It is people like this who make or break the world. But how far would you go? How far should you go? At what point do the ends not justify the means? And, perhaps scariest of all, at what point does protecting yourself and your dream actually destroy who you are?

“Someone who would never depend upon another's dream. Someone who wouldn't be compelled by anyone, but would determine and pursue his own reason to live. And should anyone trample that dream, he would oppose him body and soul... even if the threat were me myself. That is what I think a friend is.” Griffith, Vol. 12 Ch. 2  

Perhaps it is fitting that, by Griffith ’s logic, Guts’ raging thirst for revenge on Femto solidified their friendship... or at least it ensured that Guts would be chasing after him for a long time to come. Was this his last-ditch effort to get Guts’ attention? Or was it simply a matter of Griffith’s taking his own words to heart? He saw that Guts was threatening his dream, and he held onto it with everything he had. In this way, he acknowledged Guts as a friend, an equal, and an adversary.

This is where the Berserk anime ends and this is still the state of affairs in the ongoing manga. But there's another fragment of the story hidden in that "lost chapter 83"... where Griffith meets God.