Aristotle Halcyon was a 24th century celebrity decoratiste and engineer.
He was in charge of the Unclutter project, generally known as the Restore the Wonder programme. By the time he met the Eighth Doctor, the project had cleared out the asteroid belt and the Oort cloud, and was going to get rid of Jupiter's extraneous moons. While experimenting with Halcytone, he made himself blind. After the plans of Robart Falsh and Arnauld Klimt were stopped, Halcyon decide to devote his efforts to improving Earth. (PROSE: To the Slaughter)