Haunted House Historian

The Haunted House Historian is a character who knows the Backstory of a Haunted House, Indian Burial Ground, Eldritch Location, Abandoned Hospital, and other evil location. Right around the time the fresh meat-- err, "Main Cast" come in or near the evil location and start getting picked off one by one, the Haunted House Historian will intervene. He or she may exposit on the history of the haunted house, or try (emphasis on try) to take matters into their own hands to save lives and keep the house's secret.

Usually they are introduced early in the first act, and they know the terrible secret of the location either by being present, inheriting the secret from someone who was there, or most rarely, simply researching it themselves.

The Haunted House Historian is usually in the difficult position over whether to try and warn the protagonists because one or more of the following applies:
 * The secret is so incredibly bizarre that they'd be labeled as insane and ignored.
 * They were involved with the secret and want to keep it hidden to avoid jail, the shame involved, or to protect another. It may be My Greatest Failure, and they are The Atoner looking to warn away the clueless.
 * The secret is incredibly dangerous but not lethal unless tampered with, and the historian knows what will awaken or release the threat. Vehemently telling the cast to avoid X usually backfires because it makes them curious and actively seek it out and set it free. The double edge to this sword is that not knowing what will set it off means the main cast will inevitably blunder into it.

As the most knowledgeable on the threat the historian is likely to be The World's Expert on Getting Killed. However, while the Haunted House Historian does have an element of Mr. Exposition, they may only know a bit more than the characters and leave the characters to do their own research into the exact nature of the threat. They also usually form relationships with the new arrivals, and can be very active in the plot. This is exposition plus plot structure and character development.

Anime and Manga

 * The Jusenkyo Guide could be considered to fit this role in Ranma ½. He always attempts to warn travelers not to fall into the Jusenkyo springs, but his warnings are often ignored until after someone has been cursed.

Film
"Mrs. Dudley: I set dinner on the dining room sideboard at six. Breakfast is ready at nine. I don't stay after dinner. Not after it begins to get dark. We live in town, nine miles, so there won't be anyone around if you need help...
 * Mr. Harris in the 2010 Don't Be Afraid of the Dark.
 * Watson Pritchet in the original and remake of House on Haunted Hill.
 * In The Haunting, Mrs. Dudley actively plays this to scare the people staying in the mansion into being careful. Nell parodies the creepy speech she'd heard earlier back at her when she repeats it to Theo.

Nell: We couldn't even hear you.

Mrs. Dudley: No one could. No one lives any nearer than town...

Nell: No one will come any nearer than that.

Mrs. Dudley: In the night...

Nell: In the dark."


 * Ben Fischer (Roddy McDowell) in The Legend of Hell House, as sole survivor of a previous investigative team, provides the backstory of the Belasco House, called the "Mount Everest of haunted houses." He relates the evil debauchery that started it all, as well as the dire fates of his colleagues on the earlier mission. Fischer advised the others on the team to do nothing to provoke the forces in the house and wait for the week to pass so they can live and collect their fees. As the casualties mount, Fischer is persuaded/forced by circumstances to take action.
 * Pet Sematary has the fatherly neighbor in this role, who falls squarely into the "kickstart the newby's curiosity" problem when told about the indian burial ground.
 * The Watcher in The Woods has Mrs. Aylwood.

Live Action TV

 * American Horror Story has various characters who know about the house's history, but only one (Tate Harvey) who out and out warns the house is haunted. Of course, he falls squarely into Cassandra Truth.
 * The Headless Ghost, the Mandatory Twist Ending reveals that the old tour guide was a ghost all along or something).

Music

 * In the Dream Theater concept album Metropolis Part 2: Scenes from a Memory. It comes from the song "Fatal Tragedy," where the protagonist Nicholas visits the house he sees in his dream. He meets an "older man," who tells him about the murder of a young woman in the house years before.

Western Animation

 * There's a Recurring Character parodying this in South Park (specifically, an Expy of the guy in Pet Sematary). He turns up now and again to warn people away from the Spooky Location du jour.

Video Games

 * In Luigi's Mansion, Professor E. Gadd was introduced as an old man who knew a lot about the mansion...
 * Yamamura in Sweet Home, both game and the movie.