Grepoans are a sapient species of short, robust beings with beige skin, four-fingered hands, a turtle-like face and huge eyes that protrude from the sides of the head.
Assuming that Gune is a psychologically typical member of this race, it appears that they have high intellect, but are prone to behaviors that would be considered awkward or childlike by most other races. It can be confirmed that they sleep, as Gune mentions that he created his latest invention while sleeping (indicating that somnambulism can occur in members of his race) and as a result doesn't even know what it does.