Game of Thrones may be over and done, but that doesn't mean fans are ready to let go of the story yet. Some characters were given definitive endings, like Daenerys Targaryen, or at least new beginnings, like the Stark family of rulers across the Westeros continent. But try as the production might to tie up every loose end, there are a few characters whose fates are a mystery. Such as Grey Worm, who sailed away to parts unknown. However, actor Jacob Anderson's idea for Grey Worm's death makes it sound like the show knew perfectly well what his fate was, even if fans did not.
Before the Battle of Winterfell that took up all of Season 8 Episode 3's "The Long Night," Grey Worm made a promise to Missandei, his lover, and fellow Daenerys acolyte. Stuck in the snow and faced with Westerosi bigots, he promised to take her home to Naath, her island home, located off the northern coast of the Sothoryos continent.
Missandei, like many of her people, had been kidnapped from Naath as a child and sold into slavery, as the people of her homeland are pacifists who have no way to fend off violent slave traders. Grey Worm promised take Missandei home and maybe bring the Unsullied with him who wanted to go, to protect the land of Naath evermore.
However, as fans know, that's not how the story turned out. Missandei was kidnapped by Cersei and needlessly executed by the Queen of the Andals, mostly just to piss her rival for the throne off. Grey Worm was forced to stand and watch as the woman he loved was beheaded, and he could do nothing about it.
In the finale of Game of Thrones, after the election of Bran, Grey Worm and the surviving Unsullied board the remaining Targaryen ships to leave Westeros for good. Grey Worm's plan was to follow through with his promise to Missandei, and head to Naath to defend its people in her name.
There's just one small problem, as actor Jacob Anderson notes when asked about the finale in an interview with RTE. In the books, Naath is not totally defenseless. Even though Missandei's people don't fight back, the island wildlife does, specifically the butterflies. These massive creatures, with wingspans the length of a man's arm, transmit a disease known as butterfly fever, which includes a high fever, muscles spasms, and then the body's cells breaking down from the inside out. Those native to Naath are born immune, but anyone who travels there contracts it within a few hours of arrival.
Anderson apparently knew about this, but at first wrote it off. He told RTE: "Yeah but that’s a book thing. It’s not in [the] show."
Then, upon further consideration, Anderson decided actually, this was a pretty good way to die.
I mean, actually, do you know what? I want to spread [the word] that David and Dan told me that that’s real... Yeah, quote me. What actually happens is Grey Worm dies a horrible death by butterflies.
What a terrible tragedy, and an unexpected way for all of the Unsullied to die, doomed by Grey Worm's love of Missandei, and wild butterflies.