Ephem
From Tardis Wiki, the free Doctor Who reference
The Ephem were a genetically engineered species created in a "half-rate gene-splicer" to be laborers. They were made up of human biodata with a copy of a Perpetua's - their word for the Superiors - consciousness.
Being half-Superior meant that they had enhanced strength and speed as well as a connection to the flow of time, but being half-human also meant that they were mortal unless they had a copy of their original Superior's biodata which allowed them to regenerate. (PROSE: Rebel Rebel)
