Dust Giants is a Grimoire card from the original Destiny (Destiny 1), found under Enemies → Cabal. Grimoire cards held most of the game's lore and were read on Bungie.net and in the companion app, not in the game itself.
Card text
Highly trained and heavily conditioned, Dust Giant soldiers seem to be recruited from veteran Sand Eater infantry. The Cabal order of battle positions them as a mobile reserve and shock force, rolled in to blunt major Vex offensives and reinforce crumbling lines.
Grimoire text written by Bungie, shown as it appears in the Destiny 1 game files.