Arc x Ciel was one of the first times I ever realized that the route heroines in a VN have much more chemistry with each other than they could ever have with the protagonist. Shiki isn't even all that generic (though he's upstaged in every regard by his Kara no Kyoukai counterpart)- it's just that the ditzy vampire god-princess and PTSD-ridden amnesiac church executor go together like marshmallows and chocolate, as opposed to the slimy oysters that pervade Nasu's H-scenes.