Erasmus Darkening

Erasmus Darkening was an alien scientist who came to Earth in the 17th century. He posed as a magician and alchemist and was employed by Lord Marchwood, and used advanced technology to open a portal between dimensions in an effort to get home. Innocent people who were caught in Darkening's experiments and trapped between the dimensions, were thought to be ghosts haunting Ashen Hill Manor. (SJA: The Eternity Trap)