Ankoku Kishi Monogatari (WN)

Even the way I referred to myself changed from I (Watashi) to I (Boku) ever since I reunited with my big sister (her ghost).

I never heard of a vampire becoming a ghost after losing their flesh.

When a vampire was destroyed, he or she simply vanished.

I was sure that I was done for and that I was going to vanish. But, since I managed to meet my big sister at last, I didn't want to vanish.

「Don't worry Jusio. You're not going to vanish. Big sister will protect you.」

I felt something warm flowing from my big sister.

And my body healed with that.

I saw the figure of my big sister swaying, she tried to save me with her power.

「No. You'll disappear if you do that.」