The Truul are small humanoids, a little bit more than a metre. They have pale skin, often tinged in faint yellow, red, blue or green. They have hair on their head only and inte same colour as their skin.
They are an engineered race (like the Gormelites), genetically designed to lack free will and thus to be slaves. They are horrified by freedom and are not stupid. They are intelligent and know and like what they are. They don't want to live without a master, can't live without a master. They cheerfully even accept to be in the service of the cruel Kaa. They are often abused but this is considered a crime by most governments and races.
The creators of the Truul have disappeared. It is known that they were reptilian bipeds.
Source: GURPS Aliens