This deck is designed to do one thing and one thing only: Lock down the table and ensure that your opponents do not build a board presence whatsoever.
It will be cruel, it will be unusual, and it will certainly be punishment.
One thing I love as much as playing Commander itself is writing primers for decks and brainstorming. While my usual MO on TappedOut is grinding deck techs on commanders that have just been spoiled in an effort to predict how they're going to play, typically fueled by caffeine, I occasionally enjoy opening the vault and looking back at commanders that I fear have been forgotten.
One that I always told myself I'd brew around, but haven't had the chance to until today, is Horobi, Death's Wail.
The General
The Kamigawa block is one often viewed in hindsight with polar nostalgia: older fans recall how terrible the sets were when introduced to standard in the aftershocks of Mirrodin block and how many players quit as a result, but they also recall the beautiful and rich quality of the artwork and lore, as well as the solid replay-ability of the draft environment. The glut of legendary creatures in that block is another contributing nostalgia factor, and fuels "theme deck" brewing around the plane to this day.
This, however, is not a theme deck. It is designed to heavily abuse what I believe to be one of the most powerful commanders with a parallel effect ever printed: Horobi, Death's Wail.
Unlike the other Kamis of the block, Horobi does not have an unremarkable ability. Rather, it embodies the concept of "high risk, high reward" unlike any other card in the history of Magic: the Gathering that I've seen. To control it properly requires tight deck construction, considerable patience, and restraint on the part of the pilot during play.
Besides getting a solid rate for a creature (a 4/4 flier for 4 mana), Horobi has one single effect: "Whenever a creature becomes the target of a spell or ability, destroy that creature." That ability is as scary as it reads. ANY targeting effect, of ANY kind, targeting ANY creature, whether your opponents' OR yours, is an insta-Murder. This also includes enchantment auras and equipments. Only hex proof, indestructible or a protection effect can save it.
You can now see why a good Horobi deck must be built very carefully. Horobi's own ability, ironically, makes her very easy to kill. If she also came with hex proof, indestructible, or protection of some kind, she would be utterly broken. Unfortunately, it is very difficult to grant her such protection as auras and equipments will kill her too. We have to get creative.
Deck Strategy and Playstyle
This is a mono-black control deck designed to stall the game through maintaining a clean, creature-free board (at least for your opponents, anyway) until you can resolve a hard lock (Karn, the Great Creator + Mycosynth Lattice). We control the board with Horobi's power, using cheap and simple targeting effects to kill opposing creatures and commanders left, right and center.
Now, if you take a look through this deck list you will see a load of cards, especially artifacts, that are absolute garbage on their face. For real. It's hard to get worse than this. Oasis? Acorn Catapult? Nettling Imp? Norritt? Tooth Collector? Arcum's Sleigh? Baton of Morale? Where else would you play this trash? Luckily for us, with Horobi in play these cards go from bulk-bin draft chaff to completely broken, repeatable creature removal each turn. To make the cut I wanted the targeting abilities to be cheaper than Murder, and some of them are actually free! Beware, though... if Horobi is not on the battlefield (which, I'm warning you, she will have a bullseye on her back the whole game) these cards go right back to being hot garbage.
Your opponents, if they're smart, will not point their removal at those aforementioned bulk cards with targeting effects. Instead they will ensure that Horobi never survives until your next turn, with the intent of making her prohibitively expensive to recast. This deck mines as much salt as Tergrid, God of Fright
if not more. Having no creatures on board, unless you're a combo-focused artifact or spell-slinging deck, is no fun at all. To preemptively prepare for our opponents' collective backlash, we have to make sure Horobi can't be killed, and doing so is not easy.
We would run Eldrazi Monument, but this deck does not produce enough creatures to keep it around. So, instead we run Mycosynth Lattice to turn every card in the game, in and out of play, into artifacts and using Darksteel Forge to make OUR artifacts indestructible. This is the only way to make Horobi indestructible in a manner that doesn't require an upkeep payment. And, since this requires Mycosynth Lattice to pull off, we run Karn, the Great Creator to lock our opponents out of casting spells. This does not stop opponents from exiling your things prior to the lock resolution, though.
Game Progression
In the early turns, you want to build your board by playing the Big Black Mana package (Cabal Coffers, Magus of the Coffers, Nirkana Revenant, Crypt Ghast, etc) on curve. Make as much black mana as possible, and then tutor for the Lattice + Forge protection combo if you sense that your opponents' decks have a lot of interaction. Next, play Horobi and starting sweeping the board with your targeting effects. If your opponents don't run a lot of targeting interaction, begin your control of the board right away and then tutor for the Lattice and Forge. Either way, you want to ramp quickly because you will need the mana either to recast Horobi repeatedly or tutor for and cast your lock pieces.
Conclusion
I hope you enjoyed this underrated Commander deck tech. Feel free to give Horobi a whirl, but be prepared for the backlash you will receive from your table as you have the time of your life!