IF YOU ARE A PLAYER, YOU SHOULD NOT READ THIS POST. IF YOU ARE A PLAYER AND YOU READ THIS POST, SHAME ON YOU.
A new threat stalks out of the darkness of the Koronus Expanse. The hulks of fire-blackened vessels tumble derelict in the void, victims of savage ambushes. Colony townships have gone silent, ruthlessly destroyed, no survivors found. Until recently, these attacks have been scattered, seemingly without coordination. Now, as "Battlefleet Koronus" finds itself overwhelmed by increased attacks on supply shipping and infant colonies, this threat has concentrated its efforts on one goal: following an unknown siren call into Zone 51, through the Warp Gate, into the Well of Night and beyond.
The Rak'Gol have come to the Jericho Reach. None know why, but their presence in the Reach will upset a tenuous balance, and it is only a matter of time before they engage in indiscriminate conflict with the Imperium and her enemies, and it is to the Deathwatch that Crusade Command looks for answers and salvation.
The Koronus Beastiary: buy it.