The Drall were one of the founding members of the Sentient Milieu. A few fragmentary records from the Milieu era contain images of the Drall, showing them to be humanoid but unusually tall and thin — up to 3 meters in height. The images show visible gills but also show them to be apparently capable of breathing through their mouths into a lung system. This implies that they may have evolved from a gilled creature that had relatively recently adapted to life on land by developing lungs from air bladders, similar to the Earth species of mudskippers or lungfish. Comments made by the Slylandro may indicate that the Drall, along with the Ur-Quan and the Yuli, made regular visits to Source during the time of the Milieu.
In the days of the Dnyarri Slave Empire, the Dnyarri decided they and the Yuli were inferior species and not worth the trouble of maintaining, and therefore compelled the Ur-Quan and the Mael-Num to commit genocide by burning them off the surface of their worlds. Any detailed information about the Drall has therefore been irrevocably lost.