The whole idea behind the deck is to have powerful creatures to kill your opponet with. This functions primarily as a tempo deck.
Creatures - There's definitely a vampire theme going here that just allows this to work well against aggro and hefty enough for midrange decks. There's a lot of flying so the idea is to fly over our opponent's creatures and bash face. Thundermaw Hellkite is the only weakness to the deck as if our opponent casts it themselves, and we don't counter it, it can be rough.
Thurll Parasite - He's there for the extort mechanic. The life gain actually ends up being significant in aggro builds. Since we primarily have 3 drops or higher, we needed something to give us time to get there. Also, it's another way to gain life lost from Duskmantle Seer.
Stromkirk Captain - He's there for aggro builds that like to use Searing Spear to kill creatures. Also gives all of our vampires first strike so we can defend if we need to.
Vampire Nighthawk - I thought about Boros Reckoner and he still may get included if I adjust accordingly. But he provides life gain lost from Duskmantle Seer.
Duskmantle Seer - Cards are getting bigger, which means more damage dealt to your opponent, less for you. He also can provide the damage needed to cast Rakdos, Lord of Riots if our opponent has flyers chump block our nighthawks.
Rakdos, Lord of Riots - This guy is underrated I feel. He is not hard to cast and can make other creatures come out cheaper. I would love to actually abuse this a lot more but that's for tweaking.
Thundermaw Hellkite - This is the bomb to push this over the top. Either you cast him on the cheap with Rakdos, Lord of Riots or he's excellent as a 5 drop.
Overall, even though there's some higher casting creatures and Duskmantle Seer, there's really not a lot of them to be a worry. Yes, I'm sure there will be an off chance you will get unlucky but our spells are low enough and frequent enough where it is more likely we'll draw them or land than it is our big guns.
Spells - I will just briefly touch on these. Victim of Night is the best removal spell period. Boros Reckoner, Thragtusk, among a bunch of others, go down. Searing Spear gives us reach, Rakdos's Return gives us the chance to disrupt their hand and reach, and Izzet Charm allows us to counter non-creature spells, draw if we need to, or is another small damage spell for aggro. With our flying creatures, Hands of Binding can really put in work and slow down our opponents and allow us to bash face.
In general, I feel it still lacks that bomb spell. I have ideas for a sideboard but that is a concept that I'm new to since this is my first Standard deck being built. Any feedback is welcomed.