キルスティン・ホロウグレイヴ

- Affiliation: Medusa.
- Will/Gem: "Lamenting the End of Those Sorrowful Squiggling Worms" Spinel End.

A human, she is one of the leaders of Medusa organization. Possessing exceptional strength in killing Vampires because of an ability called "The Mind's Eye," she is only second to Gimelord in terms of combat power among all Medusa members.
She was a main hunting target for many Vampires because of her genotype called "Rare Blood" which caused strong attraction to them. After barely managing to escape from her imprisonment by the Vampires, she has seen that her hometown had already been destroyed by them. Since then, she has been holding an immense hatred towards the Vampire species.