Ixyldir

Ixyldir was an Ice Lord of the Tanssor clan. He led the clan from Mars to colonise a new planet. He tried to alter the technology that humans were using to terraform Hereafter to make the planet more like Mars. After being shown the error of his ways by the Eleventh Doctor, Ixyldir took the Doctor's advice and moved the clan to Atrox 881, which was already similar to Mars in climate. (PROSE: The Silent Stars Go By)