I think I should put precinct captain back in and have 3 of each him and spiteful returned. I just was having situations where he's too slow so I opted for a hasty two drop in black, but I think captain is much more powerful and has synergy with my removal to ice blockers as well as gift and gods willing for evasion. With spear he presents nice synergy as well.

No Athreos, God of Passage ? and why the Mana Confluence in sideboard. How about -1 Doom Blade and -1 Mana Confluence for +2 Sin Collector ?

The mana confluence has since become a plains and there are 4 MB now. I need to update it with the tweaking I"ve been doing on Untap.in. And the reasoning behind the SB land is that when obzedat comes in against control and midrange, the deck goes to 23 lands. You'll see in a minute. I like the flexibility it provides, because this deck can go from aggro to midrange after a sideboard. I can take out a lot of weenies for removal, and switch alms beast with obzedat, and whip with orzhov charm.

Plus I like duress and brain maggot more than sin collector, as they are smaller drops and still accomplish the same thing. I don't want to go too far off of my strategy against control/black destruction. Plus, this idea is more post rotation as i won't be able to assemble the cards in time for it to be played this standard. I'll upload a post rotation update sandbox. And I thought a lot about athreos, but decided that I'd rather have the Master of the Feast and a flex 4 drop like alms beast. He is incredible when I curve out, because they already have a lot of pressure from my 1-3 drops. Soldier=>Skyjek=>Master=>Alms Beast is a curve I haven't lost after doing. Usually I don't even need the Alms Beast unless they've had removal on my early drops.

I playtested this against my current mono black midrange deck, and your deck didn't do too well. I feel that your mana curve is too high, especially for a deck that runs many smaller creatures. I might wanna take out a couple lands, and if you intend on keeping it aggro-y, maybe a pain seer or herald of torment. If you wanna make it more of a midrange deck, take out all but a few one drops (I would suggest keeping in your solider of the pantheons, they're one of the best if not the best one drop in standard right now), and add in more midrange-y creatures like Gray Merchant of Ashpodel, Herald of Torment, Agent of the Fates, and stuff like that. You have a very cool deck idea but it seems a little unfocused.

Also put in a whip or erebos or two if you go the midrange direction.

In the description, you'll see that the sideboard is designed to take this deck from aggro to midranged for g2. I can side out a lot of 1 drops for added removal post board depending on my matchup. For control decks, I like to bring in obzedat because he's much harder to kill and gives me a slow drain each turn in addition to an attack. I have good protection for my larger creatures with Gods Willing. Against a mono black devotion deck, I'd probably take this deck into midrange for game 2 as well, with a lot of removal, duress, and brain maggot to steal things from their hand. Obzedat would be there to slowly drain life, and even if there's a hero's downfall in the picture I can still use gods willing or orzhov charm to save him. I might include the Boon of Erebos mb as a combat trick and a preventative measure, and push the gift of orzhova to the sideboard for anti aggro decks.

Yeah I'm aware of the fact that the sideboard can transform the deck, which I think is really cool and sounds very practical. I would recommend focusing your default deck as either an aggro one or an midrange one though. It looks like you have modified it and put in some more cheap creatures, which looks good. I would recommend putting in some kind of non-orzhov charm removal though. Other then that it looks good. Only thing is that a big portion of this will rotate in about a week, but maybe there's some cards from Khans that will work well.

I've made a list for post rotation here, Orzhov Aggro Warriors which features a much better assortment of aggro two drops than I previously had access to. Chief of the Edge and Oreskos Swiftclaw work very well together, and there are 8x 2/1 1 drop warriors that also receive a benefit from the Chief. This is somewhat of a subtheme, as I think master of the feast and soldier of the pantheon are good enough to include even if they aren't warriors.