The brand isn't a sign someone should immediately die as decreed by some cosmic force. It's a mark of sacrifice applied during a magic ritual. It essentially acts as a curse. The reason those who get sacrificed are usually killed right there and then is because the ceremony is performed by and for monsters, but it's not a requirement. That's why the God Hand doesn't care that Guts and Casca live: it makes no difference to them.
Well, that's wrong. See what the Skull Knight tells him at the end of volume 13. Because of the Brand, he exists in the Interstice between worlds, and as someone with a corporeal body, he's like "a torch in the darkness" to these spirits. That's the reason they haunt him ceaselessly. They crave that flesh. Flora also mentions it in volume 24. This is why I advised you to double check before replying.
Let me repeat the same thing I told
@manvsdestiny:
Your use of the word "destiny" is confusing here. Guts wasn't expected to survive the Eclipse, but there is no mystical force like "fate" or "destiny" that had decreed he should die and tried to make it so.
That goes for the reverse as well: there was no mystical force that decreed he should live. To put it simply: Guts is the master of his own destiny. He has found himself in a lot of bad situations over the course of his life, but he survived them through his own efforts and determination. While the Skull Knight did save him at the Eclipse, that was only possible because he had managed to survive up to that point. Flora puts it very nicely to Schierke in volume 24.
I'm not sure what you mean by saying the story "point towards" that. Starting with volume 22, Guts undertook a long journey to bring Casca to Elfhelm so that they could be safe, and then so that her mind could be restored. That's what he fought for. Before that he spent a couple of years fighting for revenge, roaming the land in search of apostles to kill. And before that still, during the Golden Age, he was trying to find his place in the world, to give his life meaning. With Kentarou Miura's untimely decease, we'll never get to see the real ending Berserk was meant to have, but I believe it would have revolved not only around Guts' efforts to kill Femto, but also to save his son. To me, that's what the story is currently "pointing towards".
By the way, the Skull Knight called Guts a "struggler" in volume 9, before the Eclipse, in reference to the harsh life he had led until then, right from his birth. A harsh life that meant Guts was uniquely prepared to survive the Eclipse. It's not about "struggling against a predetermined fate", but about his crazy fighting prowess and survival instinct (which we do see at work during the Eclipse). Lastly, it's worth remembering that the Skull Knight barged in there primarily to attack the God Hand. As he tells Guts at the beginning of volume 14, saving him and Casca was "incidental".