From publisher blurb:
The Nemesis Bestiary series is an outgrowth of the Space Monsters series of PDFs for the Galaxy Command (D20 Future) setting. Like Space Monsters, the Nemesis Bestiary series takes an interesting piece of stock art and builds a new creature around the art, rather than commissioning art after the text is written. Space Monsters quickly built up a menagerie of fun, original aliens and Nemesis Bestiary Volume One begins the same process.
The Nemesis Bestiary takes a somewhat unusual approach to revealing a monster’s history and behavior. While game-rule information and special powers are clearly delinated, the monster’s history, true nature and motivations aren’t. Instead, reports from the field, written by adventurers who’ve survived an encounter with the beast give first-hand, though often fragmentary and sometimes contradictory, information. The rationale is that even if your players have read the statblocks for the new creatures in this PDF, they still don’t know everything about the monster. The game master is free to improvise, expand and extrapolate as desired to build a unique encounter around one of these powerful and intriguing new beasts.