Griffith’s trajectory is the more obvious tragedy of ambition. He builds the Band of the Hawk on a pyramid of corpses, but his own tower is made of glass. The moment he believes he can possess everything—Casca, the kingdom, Guts’s loyalty—is the moment he shatters. He chooses the God Hand’s offer because it’s the ultimate extension of his dream: absolute control, but at the cost of his own humanity. He becomes Femto, a being of pure will, yet utterly hollow. His 'fate' is a gilded cage of his own design; he gets his castle, but it’s a nightmare landscape populated by the ghosts of everyone he sacrificed.
Guts, on the other hand, doesn't so much choose his fate as he chooses to keep fighting the one handed to him. His entire life is a series of reactions to monstrous choices made by others: Gambino selling him, Griffith's betrayal, the Eclipse. His 'choice' is in the relentless, grinding refusal to die. He becomes the Black Swordsman not out of destiny, but out of pure, stubborn survival. Where Griffith’s fate is a twisted fulfillment, Guts’s is an endless defiance. The irony is that Griffith, who sought to control fate, is now trapped by it, while Guts, who is hounded by a cursed fate, finds fleeting moments of purpose and even something like family in his struggle against it. The Beast of Darkness inside him is the cost of that struggle, the erosion of his own humanity mirroring Griffith’s transformation, but born from trauma rather than ambition.
In the end, Griffith’s fate is static—a king frozen in a hell of his own making. Guts’s fate is motion, a path forward stained with blood but lit by the occasional, hard-won spark of something like hope. One chose a dream and became a demon; the other had a nightmare forced on him and became, against all odds, something almost human again.