Considering, the answer is still ambiguous, I will give one last extreme copium theory on vampirism. From the angle of writing, consider why vampires exist at all. They serve to create love from others. But why must they not love, because to love would one would mean not to love many, generally. This is to say that a vampire loving a single person would be a disadvantage to the species and eventually be taboo until the point that it is feared. If Kiku lived so long and her only goal could be to find love, does it not suggest that finding love is the true goal of being a vampire. That the original vampire would be someone like Kou who could not find love, so they lived until they could. I still want to believe that there could be a happy ending in this story.
