Help with building a Mtg deck?

Mono Black Vampires is way better than Black/Green. Most good black vampires have double black in their mana cost and green doesnt support that very well. Bloodghast, Gatekeeper of Malakir, Vampire Nighthawk, Anowon the Ruin Sage, Butcher of Malakir, Captivating Vampire, Drana Kalastria Bloodchief, Kalastria Highborn, Malakir Bloodwitch, Nirkana Revenant, Sangromancer, and Vampire Hexmage, all have double black mana in their cost. All those Vampires I mentioned are good in the deck you want to build so drop the green and go mono black.