Ian, Tom and Jillian's next door neighbor, is an open-minded psychology grad student who becomes involved in Tom and Jillian's bizarre experience with the mysterious door in their basement. He eventually tells Tom and Jillian that he has a power like Jillian's and could sense her, so he sought her out to find someone who shared his condition.
Eventually it's revealed that Ian is Jillian's half-sister, and Bill is their common father. Ian unleashes his own "imaginary friend", Tall Boy, to kill Bill and get his revenge.
