It is a catchphrase associated with town guards from The Elder Scrolls
V: Skyrim. It becomes popular (meme) in a such way similar to the other known "Took an arrow in the knee", "Stop right there criminal
scum!" and the "FUS
RO DAH" meme. From
the game, you can hear the dialogue when you interact with the
NPC guards:
"You see those redguards from Hammerfell? They’ve got curved swords. Curved. Swords"
Hearing it over and over again, especially the last part where the NPCs emphasize the Curve Swords, makes it sounds funny yet somehow annoying to most players, until someone decided to
troll over the internet using this sentence. Therefore being popular and well-known to the fellow internet users.