Shadey

Shadeys were an extra-dimensional species that composed of negative energy. They fed off anger and hate and could posses individuals to manipulate their inner darkness.

Two Shadeys, an uncle and his nephew, were of a particularly wicked nature and scouted out washed up dramatist Robert Greene as he was succumbing from a fatal plague. Stirring his prejudice toward William Shakespeare for upstaging his popularity, they tempted him to murder the playright. The Ninth Doctor and Rose convinced Greene to expel the Shadeys from his body and banish them back to their dimension with the promise they would remember him after his demise. (COMIC: A Groatsworth of Wit)