The Gladius is a long-serving military light fighter spacecraft developed by Aegis Dynamics and first utilized by the United Empire of Earth Navy (UEEN) in the 26th century SEY. Its frame is easily modified, and has undergone numerous technology retrofits in the past three centuries. Beginning in the 2930s, squadrons began to phase out the Gladius and convert to newer craft like the F8 Lightning, the F7A Hornet, and the Anvil Arrow, and surplus Gladius became available on the civilian market. In 2951, Aegis increased the budget on Gladius production and invested in upgrade packages and next-generation variants of the design.

The Gladius' development began in 2573 as a replacement for the obsolete Elio-Harman Stiletto interceptor, which suffered from an inability to adapt to more modern shield components and faced increased supply chain issues following Elio-Harman Aerospace's bankruptcy. The Gladius was created for service aboard smaller capital ships that weren't outfitted for full-scale aerospace operations. It was also the first ship to introduce a civilian-style modularity into fighter design; this allowed the Gladius to be quickly upgraded or outfitted for other missions without requiring a longer stay in the hangar for a refit.

The Gladius saw widespread adoption upon its rollout in 2579. Its base model has been continually upgraded over the years, to the point that a present day Gladius Mark VI pilot would have a difficult time flying a Mark I or Mark II model.

The Gladius has seen service in almost every type of operation and engagement involving the Human military for the past three centuries and recorded thousands of kills against pirates, armed rebels, raiders, and unidentified aggressors. Anti-piracy operations, reconnaissance, search and rescue missions, jump scouting (with extended duration packs installed) and countless other roles have been fulfilled by the Gladius.

The Gladius has proven effective against the Vanduul Blade, to which it is considered a rough 1:1 match. The design suffers against the latest Blade spacecraft encountered on the frontier, although exceptional Gladius pilots have made headway in developing techniques for countering the superior alien starfighters. A safer "weave style" maneuver has also been adapted for countering superior Vanduul forces.

The rollout of the F8 Lightning has changed the dynamic for the UEE fighter force, freeing up additional battle-tested Hornets to be handed down. The Navy has begun swapping second tier Gladius units over to Hornets as more elite squadrons go from the Hornet to the Lightning. This has not impacted every duty station as the Hornet is not a 1:1 replacement for the lighter Gladius. Nevertheless, the decommissioning process has created a major surplus of Gladius hulls and parts which have been made available to civilians with their weapons technologies and other classified components removed.

Gladius and their parts are still produced by Aegis, though not in the numbers seen at the height of the Messer Era (2546 - 2792). There is an upgrade team still at work which continues to develop functionality for the now widespread civilian adoption of the Gladius.