The Perseus Hive are very different than the three other warring factions, as they are living spacefaring creatures, and not actual warships.
Protopods & Neopods
What seemed to be harmless creatures floating in space, soon turned aggressive when the Genari started exterminating them in large numbers. Over the first year of Genari Clan Moshtigh's campaigns into Hive space, some of these spores began gestating into Neopods with offensive capabilities. They began to fire back; energy beams similar to lasers were relatively weak -- but the sheer numbers of these creatures tilted the balance. In addition, what looked to be their feeding mechanism -- their proboscis -- ended up becoming something more dangerous when in proximity to Genari ships. The proboscis would penetrate the hull, and absorb any organic lifeform it encountered: Namely the crew. This was just the first step in the Hive's counteroffensive.
Surviving Neopods eventually absorb enough organic matter to grow larger, and more 'experienced', to become a Frigate-sized organism. These Neopods get classified as Protoliths, ie. the precursor to the Lith stage of the Perseus Hive evolutionary process. Everything within this creature tends to improve, such as its sensiculum, energy beams, propulsive and regenerative properties. Far more durable than their smaller cousins, they can survive extended conflict with hostile Genari Frigates.
These smaller masses are essentially undifferentiated Neopod cocoons, that will never molt into Protoliths. Scientists have not figured out why some Hive organisms never leave the cocoon, but these that are still alive generate a lot of organic energy. Somehow they can still communicate with other Hive organisms, and travel, albeit very slowly. They have been seen staying stationary in battle, as injured hive feed off the Chrysalis itself and increase their regeneration rates.