Honestly, keep the one that you use at least for section names, maybe some emphasis or something like that. Along with this font, any old-ish looking font should work. Maybe take a look at FontsInUse: search for horror shows quite a bit of Helvetica and even Times New Roman, which, added to a more stylyzed fonts, seem to work well. But maybe you will find something that corresponds more to what you are looking for :)