Xenon Q

The Q is the most feared ship in the X-Universe, despite not being the most deadly individual enemy and not being particularly potent even as M7s go. This is because it is the most common enemy capital ship encountered. Fast, powerful, highly maneuverable and constantly deployed on patrol by the Xenon within Commonwealth space with fighter escorts, these vessels are responsible for most of the losses incurred by transports and warships alike. The Q was developed at roughly the same time as Commonwealth nations developed their own frigates, possibly as a response. The vessel's design appears to have been optimized to provide a fast heavy-hitter that can sweep in and obliterate any opponent with rapidity, whether it is based at home or abroad. The Q is very fast; only the ATF Aegir is quicker in the M7 class.
As of Albion Prelude, the OTAS Astraeus Hauler and the Argon Griffon both exceed the Q in speed in the M7 class, but improvements to the OOS-combat algorithms have reduced the Q's ability to annihilate any target instantly.