Revenant

Principal Revenant is an upcoming character, and likely the main antagonist of the TV special Haunted.

Character
Principal Revenant is the principal of Haunted High, the ghost school which River Styxx, Kiyomi Haunterly, Porter "Paintergeist" Geiss and Vandala Doubloons attend. Not much is known about her at this point, other than she is extremely strict and constantly punishing her students with detention, tying them down with detention chains which prevent them from leaving the school. The frequency of these punishments seem to suggest she has an ulterior motive for keeping the students in school...

Timeline

 * November 2014: Principal Revenant is mentioned in the Haunted doll diaries.