This cube evolution of mono black agro is not much like the first decks of this kind and probably closer resemble Necro decks. Despite sharing a lot of cards with Necro this deck does not try and wear people down but rather puts them under great pressure from various angles. In this respect it is much more like Suicide Black. Black having very little depth in appropriate creatures in the cube cannot afford to be as balls to the wall as original suicide black and must make use of more disruption effects. It has very explosive mana
which can lay out some serious early threats while also having very cheap efficient creatures for one. The explosive mana can happen at any time and so your opponent should always be fearful even if you appear to just be curving out with small dorks. In addition to having lots more disruption than your average beatdown deck it also has lots more card advantage, both directly from things like Necropotence and more indirectly from the recursive creature engines. The disruption and card advantage mean that the deck has fewer threats than most agro decks and can wind up with some rather slow clocks. As it is so much less suicidal than the original constructed decks this derived from I tend to just called it mono black agro most of the time but who cares about semantics?
Black is a colour in the cube that has many cards that need support, when you play one card like Gravecrawler you find yourself wanting to play zombies, discard and sacrifice effects to optimise it. There are so many cards like this in black that you end up unable to abuse all the best cards and must carefully balance what support cards you do add and for what. Most black decks look quite similar as a result of this, with mono black agro the core power spells are alike as ever to many other black decks. The difference is the extent of the synergy support card and the general emphasis on redundancy and tempo where possible. An example of this is that both Bloodghast and Gravecrawler are very much in the deck and while it has lots of other zombies and lots of lands (...) there is no real late game way to grind out abusive advantage with them from cards like Skullclamp or Braids, Cabal Minion. Both Hymn to Tourach and Sinkhole are also in the deck but there is no other land or hand disruption to support them. If you pack too much of that kind of effect you lose any ability to apply pressure, but a little or the cream is worthwhile. Both of these cards are so undercosted and potentially brutal that they are worthy inclusions. It is in fact one of the main advantages of going agro black as opposed to any other agro colour - that you can have a smattering of power cards, some of which disrupt in ways other colours can't afford or don't have access to and normally wouldn't be able to accompany an agro strategy. Things like Necropotence and Dark Ritual and other similar effects also allow you to get away with have a few tangential cards in your agro deck.
The risk of having access to loads of black juice that is viable in an agro deck is that you become creature light. In addition to this black has quite a shallow and somewhat narrow selection of dorks which makes the power spells look relatively more appealing after you have put in the five or six outstanding black creatures and are left with the suspect remains. Being creature light is a disaster if you want to have the tempo lead from the outset and either draw badly or come up against heavy removal. The card advantage helps, as do the recursive creatures but you still really need to pack more than a quarter of you deck as dorks, ideally closer to a third. Although not the best of the one drops black does have great redundancy in cube worthy one drop tempo dorks and so you can get off to a nice consistent start by having a reliable beater to lay on turn one at the very least. The failing of the deck is usually the follow up where it fails to draw its few good three and four drops or gets them killed making it really hard to finish them off with a bunch of cruddy 2/2s. A good solution to this is playing some equipment to make all your one drops better in the mid to late game. This of course comes with its own problems as it makes being creature light even more dangerous and cuts further into your slots for power black cards. To circumvent this a little I tend to opt for equipment that is performing a role I might well be able to free up a slot in elsewhere. In this instance I am rather light on creature removal but I have Umezawa's Jitte as my only equipment to bolster the ability to remove guys while also powering up the little critters in the list.
Hymn to Tourach
Liliana of the Veil
Lake of the Dead
Urborg, Tomb of Yawgmoth
Other Gooduns one can look to include
Abyssal Persecutor (usually needs a few more ways to sac such as Smallpox, Cabal Therapy and/or Reccurring Nightmare)
Barren Moore (for the Deathrite Shaman)
Inquisition of Kozilek
Priest of Gix
Black doesn't have much reach, unlike for red deck wins your removal does not double up as unblockable damage to finish off the game. There are ways black can cause people to lose life but they typically don't hit effects creatures and those that do are prohibtively expensive. The few cards that are good enough for the cube that give agro black a bit of reach once the game has stabilized are all valuable assets in this deck. Vampire Nighthawk, while not the most serious of threats is just really good for its flying in this deck. Death Cloud is frequently used to kill people off just using the life loss portion for effect. Deathrite Shaman can ping people for two a turn and Dauthi Horror, while quite limp as dorks go, is one of the best cheap evasion dorks on offer and so covers a few important areas in the deck. Phyrexian Obliterator is a fantastic finisher and kind of offers reach but also dominates the board. Geralf's Messengers have a tiny bit of reach on them and are also the second most substantial threat in the deck which illustrates how thin the top end dorks really are. Abyssal Persecutor can be a great top end threat but with less in the way of support cards it can easily cost you games because you can't get rid of it. The list I have is one or two ways of killing Persecutor short of me being happy to play it.
Hatred is the danger card and often the card that deals the finishing blow (other than the mighty Death Cloud). They cannot really afford to tap out against you if you have a creature overlap and a life advantage, it is even risky for them if you just have a guy as you can remove their blockers. Even when you have just got a couple of land in play the burst from Dark Ritual and Lake of the Dead make Hatred usually a threat. Liliana is a bit of an oddball in the deck, she works fine with some of your recursion dorks and to some extent powers up the Hymn but really she is just a removal spell that has a bit more utility than most. While not a threat in the same way dorks and damage is she is still quite threatening for many kinds of deck and needs to be dealt with. She is not an auto include in the deck as she isn't really an agro card but she is a very powerful card that poses as a threat from a different angel and so finds herself in the same sort of boat as Sinkhole, Hymn and Necropotence, fighting for the few spots the deck has for the tangential cards.
Death Cloud is a must in this deck, without it you can easily become overpowered with things you have no hope of dealing with. It has mild synergy with some of the non-creature cards and makes it more likely you can come out of one ahead. It also works well with the recursive dorks so you can carry on applying pressure after a reset. It is you Armageddon, your Fireblast to the dome, your Mind Twist and your Bonfire of the Damned and it makes you very dangerous like Hatred does but in a very different way. Necropotence is a great fit in the deck too, your cards are cheap but offer you tempo so your life total should rarely be under much threat. You also have some burst mana so as to be able to offset the initial tempo loss from flopping out a Necropotence. Yawgmoth's Will is a very similar sort of card that works well with many of the cards I have suggested are good for Necro, it however does not provide an ongoing advantage nor is it much use early in the game. Even with all your cheap cards the initial cost of three on the Will means you are hard pressed to make it better than Council of the Soratami before the game is over. As such I rarely bother with Will and free up the spot for more dorks. With Necropotence and Dark Confidant this is an agro deck that can easily support Chrome and Diamond flavours of Mox. I often pack both although it makes getting the land ratios correct rather tough. Diamond is typically better for Deathrite Shaman, if you are splashing white for Lingering Souls etc or for added value in casting Yawgmoth's Will but either or both is good. Burst is one of your weapons and card disadvantage is not so much of an issue for you so it is always good to build with your strengths in mind.
Doom Blade and Tragic Slip are the main removal spells with Jitte, Death Cloud and Liliana offering slower back up for them. This is quite light for a deck trying to win using relatively few small creatures most of which have no evasion or ways of getting bigger. It is unwise to go with much more removal than I have as it doesn't double up as doing anything else and can sit dead in your hand. You can use more 187 dorks like Skinrender to bolster your removal count but typically they are expensive and are less effective removal than the spells. There is no targetted one mana discard either as your aim is to kill with tempo before they can ruin your day with anything too serious. Slower black decks can't beat certain cards and need to pack the discard to pluck it out before it is a problem. Even at one mana it is still a tempo loss casting something like an Inquisition of Kozilek, especially over a 2 power beater, and only trades one for one unlike Hymn and so really just stalls the game a little for both of you. They are not bad cards to include especially if the field is heavy combo and control but they are certainly very cuttable filler.
The rest of the list is a mix match of random looking black dorks which are made up of the most powerful cheaper dorks black has to offer and then some much weaker dorks trying to plug holes and fill out the curve. Vampire Hexmage for example is not exactly a ferocious beater but it is acceptable tempo for the mana and does something else pretty useful for the deck. Carrion Feeder looks quite limp but is a rather nifty utility dork in the deck and one of the only dorks you have that you can invest in like a level up monster to become a big serious threat over time. Sac outlets are useful for fizzling spells or triggers off cards as well as gaining morbid. The synergy with Gravecrawler is its main perk but even subtle things like immediately saccing your just cast Geralf's Messengers once so as to get both dorks bigger and have them lose two more life for some serious tempo.
In my cube meta this deck is very much tier one being able to beat everything out there, it even has a surprisingly good game against red deck wins. The inherent life gain on some cards, the early dorks and big threats that can come out fast are all real trouble for agro red mages. More control decks generally can't handle one or more of; lots of cards from Necro, land destruction, recursive dorks or reusable discard and have a hard time against it. Combo decks usually die to the combination of quick clocks with disruption which leaves only really the more dork based agro decks that give it trouble. Something like Zoo which curves out making continual high value and board impact dorks is just too much, your removal can't keep pace, your dorks become fairly useless and you never get ahead in tempo making many of your life costing cards rather poor. You can easily still win these match ups but you need to be a bit luckier with one of your more specific power cards or explosive draws. A turn one Obliterator is game over for a creature deck without some white removal to hand.
Do not be fooled by the disjointed selection of cards in this deck full of low power dorks and random high power spells. It has the tools to cope with most things and enough purpose to take control of games. It is a highly versatile and powerful deck that with good piloting is one of the best performing cube archetypes. I used to find it consistently the best deck on the modo cube as well until they culled the Death Cloud, you would get lots of high power late picks and it was far less hated or drafted than red deck wins.