The Gladius-class Frigate is an Escort starship used by the Chapter fleets of the Adeptus Astartes. The Gladius is the most numerous Escort vessel within most Chapter fleets, as it is one of the few Escorts in relatively uniform usage across the various Chapters of the Astartes. The vessel, although larger than any genuine gunboats likely to be in use, is small by Space Marine standards, seldom carrying much more than a single squad of Astartes who are spread across its decks and control centres supervising the much more numerous Chapter serfs upon whom the Chapter relies for actual operation of its fleet vessels. As such, the Gladius lacks the powerful assault capabilities of other Space Marine vessels, and is of little use in the planetary assaults that are the Astartes' favoured tactic. Yet the Gladius earns itself an admirable place as the foremost Space Marine ship of the line when it comes to more mundane border patrols and deep space blockades.
Like the Sword-class Frigates, the Gladius is armed only with middle-sized weaponry, but its engines are 20% more powerful than those used by the Sword-class. This allows the Gladius-class to be unusually mobile, darting into holes in an enemy starship force's line and using its weapons batteries to unusually potent effect. The Gladius-class has a standard Void Shield array for an Escort vessel, but as a Space Marine starship carries a more potent turret array than is normal for a starship of its size, which is comparable to that found on a standard Imperial Navy Cruiser.
- Battlefleet Gothic Armada, pg. 25