Gateway to Hell

What dark secrets does the ancient Templar mansion hold, and who are its faceless contributors? What force commits the people who have died there to haunt it`s corridors, and who are the mysterious ghost children that lead everyone into danger? Why is there a secret laboratory in the lower realms of the building, is this where they are creating the mutant hybrid creatures? Who controls the satanic temple beneath the old chapel, that demands the blood of innocent new-born babies for ritual sacrifice?