The sayce is a xenoc creature native to the jungles of Amarisk, on the frontier world of Lalonde. It is a dog-analogue (and is a similar size to a large Earth canine) but has a distinctly catlike appearance, with a strong, streamlined body covered in jet-black scales. The sayce has six-clawed paws and a wedge-shaped head, with flat, triangular ears, green-tinted eyes, a blue tongue and powerful jaws equipped with sharp fangs.

It is a very intelligent animal (scoring higher in intelligence than terrestrial dogs) but is also extremely aggressive, not averse to tackling a human or members of its own species. Surprisingly, the sayce is a good mimic and able to learn and speak human words; it is thus able to communicate with humans in a rudimentary way.

Although sayce are fierce predators, they are also capable of co-operating with the human settlers on Lalonde and forming bonds not unlike the relationships between dogs and humans on Earth.

Certain bars in Durringham organise savage fights to the death between sayce — a good “baiter” can earn plenty of cash for its human owner. In these fights, experience counts as much as physical strength, and a veteran sayce often has a good chance of winning. An older sayce has a generally battered and scarred appearance; ageing also has an effect on the sayce's hide, which becomes flecked with blue spots.

(Spoiler Warning)

The text below mentions events occured after 2611 and/or contains information relevant to the plot of the trilogy. Proceed at your own risk!

In a similar way to some terrestrial creatures such as cats and dogs, the sayce is capable of displaying a sensitivity to energies not usually perceived by humans; at least on one occasion a sayce has correctly identified a group of possessed as being somehow different to normal humans, and has then expressed appropriate fear and caution.