I propose we have the Tainted. Its a faction that is loyal to the Rapid Vampires. They Serve Fiora has her elite spies/assassins/scouts etc...
The Tainted were once hunters who began to dislike killing Vampires. The first hunter ever to betray the hunters, Arcadia, played spy for the Rapid Vampires. He became the first Tainted. He was gifted with fangs and the ability to drink blood along with the Elite vampire speed. Those who become Tainted serve Fiora in whatever way she desires. The Tainted can ONLY be hunters who hunted Vampires and turned rouge to join Fiora.
This is open to comments and suggestions.