The Legionnaire is a medium-sized boarding spacecraft manufactured by Anvil Aerospace for the United Empire of Earth (UEE) military. After the military failed to intervene in a piracy incident in SEY 2918, they issued an all-call for any type of technology that would help improve the success rate of boarding operations. Anvil's submission, a new spacecraft designed by lead engineer Grott Taylor, was ultimately selected and debuted in 2922.

The Legionnaire's advanced integrated infiltration system, two-in-one docking collar able to connect to all UEE-standard apertures, and trio of shield generators streamlined the boarding process and decreased the likelihood of accidents. By 2925, the Legionnaire became the centerpiece of the Navy's interception tactics package. A civilian version of the ship entered the market in 2952 during Invictus Launch Week.