Swimmers

Perhaps because their life cycle involved an aquatic larval stage, the Qu had transmuted a large number of their human subjects into a bewildering array of aquatic creatures. Taken care of by specially-bred attendants, these post-human water babies came in every shape and size imaginable. There were limbless, ribbon like varieties of eel-people, huge, whale like behemoths, decorative people who swam by squirting water out of their hypertrophied mouths and horrifying multitudes of brainless wallowers that served as food stock.

All of them were perfectly domesticated. All of them went extinct when their masters left. All save a few lightly mutated, generalized forms. These swimmers still resembled their human ancestors to a large degree; they had no artificial gills, their hands were still visible through their front flippers, their feet were splayed affairs that functioned like a pair of tail flukes. Recognizably human eyes peeked through their blubbery eyelids and they spoke to each other, though not in words and never in sentient understanding.

For millennia they swam the oceans of their ecologically stunted world, feeding on diversifying kinds of fish and crustaceans; survivors of the food stock originally imported from Earth. With the intervention of the Qu gone, natural selection resumed. The swimmers became more streamlined to better catch their fast prey. The prey responded by getting even faster, or evolving defensive countermeasures such as armor, spikes or poison. Their evolution back on track, the swimmers drifted further and further away from their sentient ancestry. They would wait for a long time indeed to taste that blessing again.