Doctor Who: 10 Villains Who Should Return For Russell T Davies' New Series
8. The Arcateenians
Created by School Reunion writer Toby Whithouse, the Arcateenians are a fascinating species first seen in Torchwood, RTD's more adult Doctor Who spinoff.
With the ability to take human form and live for hundreds of years, these ethereal beings can be scarily stealthy when they want to be (one of them, disguised as the human Mary, manages to infiltrate Torchwood with relative ease) but they're also not bad in a scrap either, with super speed, super strength, and a penchant for ripping out people's hearts. With the Doctor, that's double the ouchies.
We know that RTD loves making fun of politicians, so he'd probably enjoy whipping up a story where the Arcateenians infiltrate the government, but he could also go in the opposite direction and visit their home planet, which is mentioned - but never seen - throughout their time in the Whoniverse.
The Arcateenians also appeared in The Sarah Jane Adventures and were name-dropped in the Doctor Who episode Before The Flood, so, if nothing else, it would be cool if they got to properly complete the trifecta.