The Legend of 117

The Legend of 117 is an achievement in Halo 4. It is awarded when the player completes the Campaign on Legendary difficulty. The achievement is worth 70 Gamerpoints. It is represented by a shield in the background, with two crossed Lightrifles and a Promethean Knight skull.

Trivia
The achievement's name is a possible reference to videogame series The Legend of Zelda.