Legionary 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
Propelled by jump packs and wielding powerful slug rifles, Legionaries are the Cabal's line infantry and the backbone of their military power on the ground. Common Legionary tactics center on the bounding advance - some units attack the target while others close the range or find new firing positions.
Grimoire text written by Bungie, shown as it appears in the Destiny 1 game files.