From publisher blurb:
This expanded Rpgue's Gallery of Brood variant evolutions and agents of the Hive adds eight fearsome new opponents to the Post-Fall world of SINS, including:
New Alpha, Gamma, and Delta-Strain Brood Evolutions
Unique Broodspawn types
The first of the True Hivespawn
New Broodspawn Evolutions
The Broodspawn are an ever-changing foe, existing in a vast array of forms. Beyond the more commonly known Strains, there exist a number of rarer, more specialised adaptations. Each new strain includes Pack Advantages and Special Requirements, unique to them, as well as new Broodspawn.
Delta Strains
These are the engineers of the Brood, moulding the environment to better accommodate their Horde. Their role is to build "infrastructure" to support the roving horde, providing a place to breed reinforcements or for a defeated horde to retreat to and lick its wounds. Unlike Alpha, Betas, and Gammas, Delta subspecies don't emerge spontaneously; they only evolve under the guidance of an Alpha.
Mercurials
Though the Brood is an ever-changing, ever-evolving threat, some strains take the adage “what doesn’t kill you only makes you stronger” to a whole new level, setting them distinctly apart from their kin. Solitary and predatory in the extreme, the Mercurials possess a terrifying ability to adapt and alter their forms in response to a threat.