[Spoilers for the final season of Game of Thrones]
The final three episodes of Game of Thrones were death-filled ordeals with Missandei, Varys, Euron Greyjoy, Qyburn, the Mountain, the Hound, Jaime Lannister, Cersei Lannister, and Daenerys Targaryen, among others, not making it out of the series alive. A surprise non-casualty, however, was Grey Worm, the commander of the Unsullied who, after half-heartedly accepting Jon Snow’s banishment to the Night’s Watch for the crime of killing the queen, sailed to the Isle of Naath, his girlfriend Missandei’s homeland. And he lived happily ever after… except there is no happily ever after on Game of Thrones.
Naath is a lovely island in the Summer Sea with white beaches, tall trees, and deadly butterflies. Missandei and the rest of the Naathi have grown immune to the “butterfly fever,” but foreigners haven’t; here’s what Grey Worm and the Unsullied can look forward to: “A large species of butterfly on Naath is a carrier for a horrific disease that makes the flesh literally slough off of a man’s bones, but the Naathi themselves are immune to it. For centuries, would-be foreign invaders would end up succumbing to the ‘butterfly fever,’ and the Naathi say none maintained a presence on the island for more than a single year.”
So, yeah, R.I.P. Grey Worm.
The disease was never mentioned on the show, only in George R.R. Martin’s source material (including The World of Ice & Fire: The Untold History of Westeros and the Game of Thrones), but there is a nod to Missandei’s roots in the opening credits: Nathalie Emmanuel’s name appears next to a butterfly.
Bart Simpson was right: nobody ever suspects the butterfly.
(Via Game of Thrones wiki)