Something stalked my Grandfather during the Great War

I found my dead grandfather's diary in the cellar. I never knew my grandparents that well, they died when I was five. The house stayed in the family, for some reason my parents decided never to sell it, and in time I came to know it better than I ever knew my Grandpa or Grandma. It was an old place, a century house, full of drafty corridors and hidden crawlspaces and stairwells that lead to nowhere. We didn't go to the house often; I realize now that my Dad only spent that time in the summers there to fix up the place. I suppose in his mind he thought he'd sell it one day. But that day never came.