With some relative success it seems appropriate to begin some discussion on the deck and the archetype. There have been many mono-black aggro threads in recent memory (I just did a search for them), but none actually seemed to go the route of Suicide Black instead opting for more a black weenie strategy or a Confidant based approach ala Deadguy Ale.
The deck is based around using very powerful creatures to finish off your opponent using disruption as means to that end. The main difference between this deck and the decks that have been discussed in mono-black threads is that the creatures in this deck by and large can end the game all on their own. This deck is tempo-driven by this I mean it wants to play something that will affect the game immediatedly as possible. While draw spells are always important and helpful, this deck cannot spend the precious early turns of a game trying to generate card advantage. It simply doesn't win because it has more cards in hand but rather because its disruption has allowed its creatures to seal the deal.
I played the following deck to a 9th Place Finish at the most recent StarCity Duel for Duals -
//Disruption
3 Pithing Needle
4 Hymn To Tourach
4 Sinkhole
//The Legion of Doom
4 Wretched Anurid
4 Nantuko Shade
4 Hypnotic Specter
4 Phyrexian Negator
//Removal
4 Vendetta
4 Diabolic Edict
//Mana
4 Dark Ritual
4 Wasteland
17 Swamps
Let's go over each section to explain the way the deck works.
Disruption
Pithing Needle - I decided to play Pithing Needle over Duress because I wanted to improve my game against Goblins and other aggro decks where Duress is either very poor or just outright dead. At this tournament Pithing Needle ended up being different levels of effectiveness - amazing against aggro but much worse against combo and control. I think this is mostly a metagame call, but currently I'm favoring Duress over this card but boarding Needle can be a very good choice.
Hymn to Tourach - One of the best ways to disrupt your opponent is to pull two random cards from his hand on turn 2. This card acts like the best Duress (pulling the two most relevant cards) or like a double Sinkhole (pulling two lands) or often just a good mixture. The card is amazing against combo, control, and aggro.
Sinkhole - There's nothing like robbing tempo from your opponent when on your third turn you untap and play your third land, but your opponent only has 1 in play because you played a turn 2 Sinkhole. Its that window of opportunity that a deck like this lives and thrives off of.
The Legion of Doom
Okay I like my creature base in this deck so much that I've gone so far as to give them a name - The Legion of Doom (based on the old cartoon Super Friends). I was also given the suggestion Cowboys From Hell (Pantera album) on Saturday (thanks Asher) which I find pretty cool as well.
Wretched Anurid - He's a recent addition and substitution for Flesh Reaver. While I love the Reaver's power and speed but against decks playing creatures he just often turns himself off by by losing so much life. Anurid can also cause a great deal of lifeloss (and uncontrollable I might add), but he's much better about being chump blocked. I'm still not certain which one is best in the current metagame, but both are powerful 3/3s and 4/4s for 2 mana.
Nantuko Shade - While not the best turn 2 play, he's definitely amazing often swing for 5 damage starting on turn 3. He ends the game unblocked within a few turns. He makes all of your post third turn rituals into giant growths. He eats other creatures for a living.
Hypnotic Specter - You might think he doesn't end the game quickly because he's a 2/2, but in fact he does end the game just as fast as the other creatures, because he makes it so that your opponent has to top-deck the answer since he shrinks your opponent's hand very quickly. He is one of the few ways the deck can actually generate card advantage.
Phyrexian Negator - Negator in a format with creatures! Must be a mistake! No mistake at all. In fact the mistake is that people think he's terrible in this format because Goblins exists. To be fair I thought he would be terrible against Goblins myself, but I've beaten Goblins with him so many times I know he is good against Goblins. A 5/5 on turn 1 is nuts that's all you need to know. There is no other deck in this format that can boast that. I would never play this deck without Phyrexian Negator.
Removal
This is part of the deck that I really had to work on for Legacy. Older Suicide Black decks were often based in non-creature formats (ie Type 1). So I figured I needed to dedicate some of the main deck to removal. This would serve two purposes - Kill my opponents creatures, but more importantly force my creatures through which is what the deck needs to be able to do win games.
Vendetta - There are many 1cc removal spells, but none are as versatile as Vendetta in this deck. Sure the lifeloss is an issue, but the important thing is that you can play this card on turn 1. Having an answer for Goblin Lackey as well as being able to hit almost any creature (black creatures being the obvious exception).
Diabolic Edict - As a secondary removal spell it has impressed me time after time. While it seems terrible against aggro decks the main benefit of this card its the least likely to be dead. Suicide Black has no draw as currently constructed so it has to make it least likely for it to draw a dead card. Diabolic Edict is dead so infrequently it makes for a very good card in this deck. Its often even useful against combo decks (Spring Tide, Salvager's Game, Belcher, etc.)
Mana
Dark Ritual - This is another reason to play this deck. It allows for you to generate so many busted openings that this card is integral to the deck. People often think that you need this card to win, but that just isn't the case. If constructed correctly Dark Ritual only increases your tempo and doesn't rely on it exclusively.
Wasteland - Another disruptive element that both generates tempo and disruption all in one card. It complements the Sinkhole strategy very nicely and often allows for generating so much tempo by your opponent missing multiple land drops that you win because of it.
Swamps - The reason to play 17 is to make sure you hit your second swamp on turn 2. I can't stress this enough. The surest way to lose tempo is to not be able to play your spells on the turns on which they are suppose to be cast. I've tried running 18 but I have not seen no major improvement in hitting the right amount of lands.
Matchups
Goblins 40/60 Preboard - When I first put this list together I thought my game against goblins would be terrible. To be fair this was last summer before Goblins really took off, but I was suprised to find that this wasn't the autoloss. Preboard games are difficult, but very winnable. You want at least 1-2 to creatures in your opening hand and hopefully a removal spell as well. If you are running Duress - hope you don't draw it since its the most dead card in the main deck. Post board games get much easier with boarding Infest and Pithing Needle. The reason no Engineered Plagues in the board is that this deck can't reliably find 2 Plagues because it lacks draw. Instead you Infest their team and drop a creature and swing in for the win.
Threshold (Gro) 50/50 Preboard - The different flavors make a big difference. The black version is most favorable for you because they're removal is often dead. The white version is pretty close, but often they just drop Mystic Enforcer and you lose (unless you have the Edict!). The red version also sounds difficult because bolt on a Negator is a never a good thing, but in actuality you can protect your Negators with Duress, Hymn, and Sinkhole. Going after their manabase can often be a successful strategy. The game usually goes to which player can get his creatures to stick. While Sui's creatures are better in the early game and Threshold's creatures are better in the mid game it becomes quite a battle to see which creatures make it through.
Solidarity 70/30 Preboard - While this may seem like an auto win it is not. While you are heavily favored you can often lose because they can go off through your 1 or 2 disruption spells. Remand has been a huge help to Solidarity in this matchup. But you usually win because you have disruption plus a fast clock. Your creatures will never look as good as they look in this matchup. Sui still loves to see Mono-blue decks!
Rifter unsure - I haven't tested enough to really have a sense of how the matchup goes. When I did test against Wombat it was slightly favorable perhaps about 60/40, but Lightning Rift itself can be quite the problem, but again the manabase is more open to disruption. Its hard to say at the time of this writing exactly what that matchup is.