Monaxi

The  were a "trader" species which sold "lesser" species as slaves to "more developed" civilisations. (COMIC: Medicine Man)

The Monaxi worked with Mister Ebonite to capture individuals and put them in the Arena of Fear. (COMIC: Arena of Fear)

Biology
The Monaxi were a composite of matter and energy. They looked like ornate flying saucers. But this was just a protective shell. Their true form was a grotesque head with approximately a dozen small eyes, a large mouth with serrated teeth, and a large number of tendrils under their head (12-18). Their entire body was enveloped by an energy carapace making them an extremely hardy race. This could, however, be penetrated by a sonic screwdriver. The resulting shock would stun a Monaxi. (COMIC: Medicine Man) The size of individual Monaxi varies, from individuals a few ft taller than humans to ones x3-x4 as tall. (COMIC: Medicine Man, Arena of Fear)

Culture
The Monaxi are an ancient race of interstellar slavers who used Earth and a number of other "primitive" worlds as hunting grounds where they would capture potential slaves and sell them to "higher species". Depending on the buyers the slaves could end up as entertainers, gladiators, food, and so on. The Monaxi looked down on all bipeds such as humans or Time Lords who all looked the same to them. The governing authority of the Monaxi is the Monaxi Guild and the race has had dealings with the Time Lords in the past. (COMIC: Medicine Man)

Technology
Monaxi possess a variety of technologies. The protective shell which also functions as mode of transportation (flight) is equipped with energy beam weapons, tractor beams, and energy nets. Holographic technology is used to create environments (deserts, rivers, forests, etc) to test the enslaved to determine their abilities and suitability as slaves. (COMIC: Medicine Man)