The Koldasians are the inhabitants of the Planet Koldas.
According to Branton, the Koldasians are a humanoid species, but -just like the Dal- they are not from within this Universe. Still, they would be members of, or at least have very close ties with the Federation of Planets. Branton also claims the Japanese government has contact with them. (Dreamland & Dulce 30).
(Actual Source: UFO, Contact from the planet Koldas - a cosmic dialogue.The book describes the relationship of a South African of Durban with a Koldasian, called "Valdar").