Fans have already decided how to end the manga… And Griffith’s fate is unenviable.
“Griffith did nothing wrong” — if you are bold enough to say it — be ready to receive a pack of hateful comments or to be praised for your bravery. Let’s think about how we ended up in this situation. There is a lot to cover — starting with the Golden Age and ending with the last chapters of the manga, so be ready for spoilers.
Let us start with Griffith's background. He grew up in poverty, looking at the castle which he wanted to acquire. He played with other children, but he was much more ambitious than the others. And one day he received the Crimson Beherit from a gypsy fortune teller, who predicted Griffith’s future victories around the world. Later he formed the Band of the Falcon and found Judeau, Corkus, Pippin and Casca. Griffith wanted to fund and to upgrade his band to win more and more, which would lead to fame. That’s why he sold his body to the Tudor Lord Gennon, who helped Griffith in return. We can already see the development of Griffith’s ambitions and dreams of conquest — he would do anything to achieve his goals.
Some time later, Griffith meets Guts and “acquires” him during a fight. Guts ends up in the Band of the Falcon and becomes the captain of the raiders. Moreover, Guts becomes almost equal to Griffith, but he leaves the band. Griffith wants to stop him with a duel, but loses because Guts’ motivation was much more powerful than Griffth’s ambition to control everything around him. He seduces Princess Charlotte, which leads to Griffith’s torture in the Tower of Rebirth. A year later, he is saved by Guts, Casca and others, but he is no longer able to fight or even speak.
Everything led to the Eclypse, when Griffith sacrificed his comrades and became Femto, a member of the God Hand, but he wasn’t able to return to the material world. That’s why he later reincarnated as Griffith (but now it is Femto in physical form). He encounters Rickert, Guts and Casca on the Hill of Swords and says he doesn’t feel anything. After many events, he ends up in his dream kingdom of Falconia and forms the new Band of the Falcon.
We may already say that Griffith is selfish and will do anything to achieve his goals… And it’s true, many fans hate him for that. They come up with ideas on how to kill him at the end of the manga. But some people love Griffith not only for his appearance, but also for his development as a character and how well-written he is. This makes Griffith an anticipated character, and his story has to end properly. The fans came up with many ideas. The following two we found the best. The first one is quite simple, but sad. Guts manages to kill Griffith because he does not want revenge, but out of compassion. With Griffith’s death, Moonchild also dies, leaving Guts and Casca without a child, only sadness. The second one is more complicated. If we consider Griffith and Moonchild as different entities, Griffith’s death would lead to his nightmare, where Casca was his wife and Guts was their child. But now he would be a child instead of Guts. Everything that Griffith had achieved would vanish in his nightmare that would become a reality.