Viskopan Guardian

Flying
As long as you control a vampire, if it is black, Viskopian has deathtouch, if it is white Viskopian Guardian gets +1/+0, and has lifelink.
"Orzhov vampires look for allies in unlikely places
in case their new guildmaster turns on them. The fate
of the Obzedat is proof of Kaya's power and her
hatred of the living dead."