I've been rewatching Game of Thrones from the start in anticipation of the final season, and I chanced upon a curious line in the third season's opening episode. Dany is presented with the Unsullied and she is told that, and I paraphrase: "they practice tirelessly to master the shield, the spear and the short sword".
The short sword? Have they ever shown the unsullied using anything other than the spears on the show? And yet there have been numerous moments on the show where the sword would clearly have been the better choice. Most notably in ALL of their battles against the Sons of the Harpy (including the fight that killed one of the best characters on the show, and indeed the books).
Did the showmakers forget about the whole thing, or was Dany sold a batch of Unsullied that never learned that weapon?