Personally, I run a monoblack list as well, and I prefer Erebos as the commander because he helps clock the game out, and provides repeatable card draw on a very hard-to-kill body. Granted, my list is more control-attrition meant to slowly drain the table's life points and swell my own. Then I spend that life on cards.

Strata Scythe might work out better than Lashwrithe, or included next to it simply because of the interaction with Urborg.

Syphon Mind is great card draw for multiplayer.

Sudden Spoiling is often a huge game-changer. With as many fliers as you have, this will remove any flying defenses they may have, and it stops creature based combos.

Heartless Summoning would be okay for you since you run fairly few creatures to get axed by it.

Best of luck to you!

ecmmyers thanks for the suggestions. I've been using Sudden Spoiling but I've seen mixed results. Syphon Mind is probable and I will definitely try to make room for Heartless Summoning. Not sure about Scythe though

+1
I like this deck, you've put a lot of thought into it. Altar of the Brood for the extra mill maybe
I've a similar deck but its GB, it's only casual so it doesn't matter.
Doesn't matter how many times you do it, whenever you steal something with Geth, make horrible "get" puns. Like "I'll Geth your sol ring", "I need to Geth more things" or "Get it? Ghet? Get it?"

PremiumCola I actually have an Altar of the Brood still somehow (I thought I burned them all because my play group hates that card), I'll consider it

I thing that Liliana Vess would work very well in this deck

Crazedmage She doesn't actually get me that much value. There are better ways to get cards into my opponent's graveyards than discarding, and I'd honestly much rather just use Demonic Tutor or Sidisi, Undead Vizier if I'm going to go grab cards from my deck, because they add whatever I tutor for to my hand rather than placing it on top of my deck. Her ult, while potentially game-changing, isn't going to happen enough in my play group to make it viable. I do really like the card and would run it in a discard or devotion deck, but she just doesn't get it done for me here.

So, why no Thran Dynamo or Worn Powerstone to further abuse Geth's (Or Drana, or Erebos') activated ability? I can't help but suspect that either of those would be a bit more useful than Orbs of Warding. Even a Crypt of Agadeem could net a few extra per turn with your self mill.

If you want to trim your curve, Grim Haruspex is pretty good for that, although the body is a bit lacking compared to Harvester.

If using life as a resource, Killing Wave is hard to play around for opponents. Since it's sacrifice, it dodges indestructible and hexproof/ shroud. One thing to consider when comparing to Dregs is that it helps those who have few creatures (e.g. voltron) and punishes tokens. I was just never a fan of the minimum 6 CMC of Dregs.

Praetor's Grasp yoinks a Sol Ring even without needing to mill it, in addition to possibly neutering a win condition/ permanent you can't deal with through conventional removal.

ecmmyers I've had Crypt of Agadeem in the deck before. There has literally never been a time I hadn't wished it were a Swamp instead. I don't keep my creatures in the yard long enough for Crypt to net me anything. Haruspex really isn't that great because even though I get draws off of other creatures dying, Harvester gets me draws from everything, and Haruspex only counts my creatures. Plus, Haruspex doesn't have deathtouch to allow it to trade with something bigger than it and draw me a card. Killing Wave could be fun for dealing with people's boards, especially if my life total is significantly higher than those of my opponents. Thran Dynamo is a great mana rock (as is Worn Powerstone, but Powerstone is held back by CIPT) but the issue is how to add it without hurting synergy. Praetor's Grasp is also a fun card that will be taken into consideration

Those are all very fair assessments.

If you wanted to add Dynamo, I'd cut Orbs because I don't personally see the synergy/ utility in this deck, unless your meta has lots of player targeting. (Even then Witchbane Orb is more reasonable because of the cheaper cost despite the damage reduction, IMO, assuming minimal token presence in your meta).

Other cards that I personally perceive as weaker/ overcosted are Dregs of Sorrow, Desecration Demon (Do you ever get to attack with it?), and maybe Hell's Caretaker (since it dies to Heartless Summoning). If you were looking for cuts.

ecmmyers my meta has lots of people who like Impact Tremors. Orbs prevents all those iterations of 1 damage. And yes, most people don't tap Desecration Demon down because they know what the deck does. And yeah, Caretaker does die to Heartless Summoning, but with it being my primary recursion method, plus the fact that Caged Sun + Heartless Summoning means my stuff doesn't die to Heartless Summoning means I'm willing to stick with Caretaker. I can agree though that Dregs does cost a lot for what it does.

I'm not sure how Orbs prevents the damage, since Orbs of Warding prevents damage from creatures only, and Impact Tremors (an enchantment) does the damage itself. Furthermore, effects with 'each' do not target, unless the ability explicitly says 'target' in the rules text of the card.

ecmmyers ahh you're right, it doesn't prevent that damage. Well then I guess it can get cut for something better.

Maybe Platinum Emperion to reanimate if you're worried about Tremors. It does shut off life as payments though.

I don't know how you feel about infinite combos but since you already run Necrotic Ooze you could add Palladium Myr and Pili-Pala to make infinite mana to mill your opponents out in 1 turn or Exsanguinate them to death.

Squirrel_of_War infinite combos are nice but it seems rather difficult to set that up honestly

Buried Alive will set that combo up fairly quick. Palladium Myr is good on its own too. Adding the combo will add another layer of depth to your commander deck, if it was easy to set up it wouldn't be fun. I'd say give it a try and let me know how it feels to mill the entire table to death on the same turn. :)

Mindcrank seems like a good fit here. Maybe even add Bloodchief Ascension to top it off.

ManSauce Mindcrank, that's a thing. It's definitely a thing. I dunno about Bloodchief Ascension. I mean I love it in a Rakdos, Lord of Riots deck, but I'm not sure about here

I can't believe you haven't thought of Scythe of the Wretched and even more important Debtors' Knell!!

chatmort can't play Debtors' Knell, its color identity is black and white

Well, the combo of Mindcrank and Bloodchief Ascension is an insta-kill for any opponent that takes damage and you gain a whole bunch of life. In EDH its easy to get Bloodchief to 3 counters in one round, provided you have 3 opponents, so they will have to deal with it quickly. And for a total of three mana, that's pretty sweet. I guess it depends on whether or not youre cool with infinite combos, but in my opinion, this is one of the not lame ones.

ManSauce I love infinite combos, but at the same time, this is that one deck I DON'T want to go infinite with

Platinum Angel seems out of place here.

sebvieira true, while the ability to not die is nice, it dies to removal way too easily. Plus now that I've picked up a reliable token maker I can put my token mill engine back in

Chainer, Dementia Master, Puppeteer Clique and Sepulchral Primordial are all good for taking things from graveyards and getting multiple usage out of them