Who is Marcus Beaumont from Haunted: A Tale of the Mediator and what is their importance?

Marcus Beaumont is Red Beaumont's brother and Tad's uncle. When Red starts to act delusional, Marcus takes over running the development company. Marcus turns out to be the one responsible for killing and getting rid of the bodies of the environmentalists who are trying to stop the development projects. At the end, the ghosts of the people he killed are haunting him and he disappears from the Carmel area.