At least 56 assault fighters were preserved underground with a Vaadwaur battalion through the orbital bombardment of the Vaadwaur homeworld in 1484. They were reactivated in 2376 with assistance from the USS Voyager crew, with the intent of helping to break through the Turei fleet gathered over the planet. However, the Vaadwaur attacked Voyager instead in an attempt to take its technology. Many of the fighters were subsequently destroyed by the Turei, after Gedrin transmitted targeting data from a Vaadwaur sentry satellite to them.
During the late 15th century, these assault fighters were said to be very advanced, using the underspace to raid, destroy, or even conquer neutral parties or enemies. After the bombardment of the Vaadwaur homeworld, the technology of the fighters become little more than antiques against more modern vessels. (VOY: "Dragon's Teeth")
These assault fighters were armed with particle cannons that fired rapid pulse beams into enemy vessels, giving them an ability to inflict a large amount of damage on enemy ships within a short amount of time. However, they lacked photon torpedoes or heavier ordinance. But despite their weaponry, they were less than useful against more modern starships and the aggressive species in the Delta Quadrant. Despite their firepower, their shields were not able to withstand a single phaser blast from an Intrepid-class starship, causing the ship to explode instantly. (VOY: "Dragon's Teeth")
The orginal concept art for the assault fighter was sketched by art director Tim Earls on 26 July 1999, but the design was rejected in favor of the final design, designed and build in CG by Foundation Imaging. (Star Trek Voyager: A Celebration, p. 209)
Star Trek Online's 2014 Delta Rising expansion features a full line of Vaadwaur capital ships extrapolated from the assault fighter of Star Trek: Voyager. The fighter itself, dubbed Pythus-class, was added to the in-game Lobi store for the game's 2015 fifth anniversary celebration.