Since you are running monoblack I think you may be able to get away with 22 lands instead of 23. If you do that.....
-1 Swamp
+1 Blade of the Bloodchief
Also, I do not know if you are using this for casual play or not, but I would recommend getting some dark rituals in here.
Vampire nighthawk on turn one?!?!?!?!?!
If you want to go the dark ritual route I would suggest:
-3 Swamp
-1 Blade of the Bloodchief
+4 Dark Rituals
If you have a dark ritual you can play any card in your dark on the second turn. You can possibly go into turn three with a 5/4 flyer with Vampire Nocturnus.... not bad. Not to mention with less lands Nocturnus' ability is even stronger. Maybe add some terramorphic expanses to help thin your deck out to make the ability as close to as 100% effective as possible.
Just some ideas/suggestions.