One who is in the process of application to become a In a word, vampires. There are two branches of Night-Childre... in Notte’s family. Only humans can be turned into vampires, and the human has to pass a series of tests and take a number of classes both before and after turning.
He’s one of the oldest living beings among the Mythos. The... is pretty darned picky about who’s allowed to be turned.
As an aside, A vampire, and Notte’s oldest surviving child (not his fir... takes whomever she darned well pleases, but she has to keep them under the radar.