In popular usage, the word is associated with the White Wolf roleplaying game "Vampire: The Masquerade" (later "Vampire: Requiem"). In this context, the word (usually capitalised) is used to refer to a single vampire, a group of vampires, or vampire society as a whole.
(It should be noted that this usage is a little awkward when used to refer to a single individual. Since the word 'kindred' defines similarity it therefore implies plurality.)
"He's one of the Kindred."
"This group could threaten all the Kindred in this city".
"yeah its is."
"she is smokin."