Prince Velrav, Blood Prince

Vampires you control have "{t}: Counter target planeswalker activated ability."
Spells you control that target vampires you control and planeswalkers you don't control cost {1} less to cast.
Pact (You can have two commanders if both have pact. If the two commanders share a creature type, they cost {x} less to cast, where X is number of times the commander's been cast.)