Abbysial

1 Utter End, 1 Hero's Downfall and 1 Crackling Doom. these are strong cards, but this being an aggressive deck you don't want too many non-creature spells

I think 4 dragons may be too many, he already has Zurgo on the top as well and i believe it is better to play both than to choose, since they are devastating against different decks and they are both strong overall

the reason i say Herald is better is:
1st: Master of the Feast gives negative card advantage where herald costs 1 life each turn. I it much easier to race a -1 life than a card each turn.,
2nd: Herald can be bestowed, which can either make your early game creatures scale better into late game or give your already powerful creatures flying to evade blockers and some ekstra power to finish him faster.
3rd: a bestowed herald takes 2 kills, or an enchantment specific kill to get rid of

yes master is strong, but i've rarely casted a turn three herald. though it ain't a bad move in itself

Awesome deck, i have a few thing i would change though.
Beave is right to suggest Goblin Rabblemaster, but i can easily follow you in the fact that Bloodsoaked Champion is cool.
My suggestion is to take out Generator Servants and maybe a single Zurgo for Rabblemasters

I played the mono-black aggro before the rotation and i must say that i am amazed of how well Herald of Torment works. I would replace your Master of Feasts with Heralds of Torment

Have you considered 4 Bile Blight?
it is an excellenct removal because it's a great threat against the creature that wins most matches in itself; Pack rat.

Also i'd remove Read the Bones completely from the list and run 4 Underworld Connections to maximize the card advantage you can make, it draws cards and the opponent need to remove it to keep up with you.

I wasn´t saying it couldn't do it. i just said that i think that Downfall is better than Dreadbore

Nice deck, but you might wanna think of exchanging Dreadbore with the new plainswalker/creature kill "Hero's Downfall". It costs 1 more colorless mana, but you get the advantage of it being instant-speed.

The deck looks awesome, but if i were to change something i would take out Doom Blade and Dreadbore and put in another 2 Hero's Downfall.
Doom Blade vs Hero's Downfall; Downfall ignores the weakness against black and hits plainswalkers.
Dreadbore vs Hero's Downfall; Downfall costs 1 more colorless, but i would gladly pay that to achieve instant speed on a kill.