Legio I Libra is an Aestrucasian Legion dating back to the founding of the Empire. The legion is the oldest legion in the military, it has also been involved in various battles and engagements, including the Aestrucasian Civil War, to name a few.

The Legion uses the standard-issue body armour, the Lorica Kevlare, the body armour is light and can withstand small handgun cartridges, (9x19mm, .45 ACP, etc.). The Legion also uses the Galea Kevlare, a helmet made out of kevlar to protect the wearer's head to some degree.

The Legion used short-swords known as a 'Gladius', but when time progressed these were considered obsolete. In modern times, the Legion uses assault rifles, battle rifles, and pistols for officers. Spears were also used and were known as 'Hastas', but these were for throwing, these spears will bend on impact so that it would be useless, and to ensure enemies would not use it in battle.

Nowadays the Legion's soldiers use the A-20 Magnus assault rifle, while high-ranking officers use the A-17 Maximinus pistol.

Like other Legions, Legio Libra has a legate, the legate is appointed by the Emperor to command the entirety of the Legion, over 719 Legates have commanded the Legion, it shows how old and how much authority Legio Libra has.
The current Legate is Legate Hestasius Maximinus.

The Legion has 300,000 active personnel.