Re'nar

The  was an extra-intelligent lizard-like reptile from the Matrua Nebula that had been at war with the Ju'wes.

Biology
Both the Re'nar and Ju'wes were larger than a man when standing in a hunched bipedal position. They had sharp teeth and claws and long tongues. Their forelimbs had hands with four fingers and they walked on the two digits of their hind limbs which kept their dewclaws off the ground. Their tympanic membranes were close to the surface and their hides were thick enough that they could deflect bullets. Re'nar were leechers that could go without feeding for weeks and could see the chemicals radiating from the bodies of their prey. Mac'atyde had a green coloured skin. (COMIC: Ripper's Curse)

History
Hundreds of years after the 19th century the Re'nar and Ju'wes engaged in a war during which both sides did terrible things. The Ju'wes won the war by being willing to commit self-sacrifice. After the war most atoned but the Re'nar Mac'atyde continued to murder and was pursued by a Ju'wes who considered it his personal responsibility. Both crashed their ships after they fell through a time rift to Earth in the year 1888. Mac'atyde attempted to alter the course of the war by framing the Ju'wes race for the brutal Jack the Ripper murders but the Ju'wes took the place of Sir Charles Warren to try to stop him. (COMIC: Ripper's Curse)

Behind the scenes

 * The Re'nar and Ju'wes might be the same species. Skin colour is the only obvious difference between Warren and Mac'atyde and it apparently doesn't make a difference to the Doctor who had already seen Mac'atyde undisguised.