When you get a chance id try and take out some of your one ofs and make more consistant creatures. For example id take out Executioner's Swing and two other one ofs for 3 Tragic Slip

By one ofs you mean cards like Murder ? Yes, I'll definitely consider that. However, wouldn't it be best to remove just one Murder instead of two? I mean, Tragic Slip is good, but only if a creature died that turn. If I could, I'd rather prevent that from happening. Maybe taking out some other card in place of that second Murder?

@chaosindafridgeWell, after thinking for a while, maybe killing creatures to make Tragic Slip effective IS what I want. Where did I have my mind when thinking that I would have to be the one losing creatures? :P Added 3, along with some more removal. And some other massive overhauls.

So if your plan is to stall till you can cast Debt to the Deathless I would suggest a few changes. I would run Blind Obedience instead of Martial Law as the obedience will help sooner and better against agro then the Law. And I gotta say I'm not a big fan of Desecration Demon either, I just dont like giving other people the choice to tap my stuff. Maybe also the Sin Collector and add a couple more Duress . I might even with this cut the creatures to Crypt Ghast High Priest of Penance and Vampire Nighthawk and then add some more removal. Barter in Blood would be good if you are only running a few creatures as you are less likely to have them on the field, Mutilate is another really good board wipe for you. And of course Obezdat is of course a great card.

Good luck with the deck

Although Blind Obedience has a more attractive mana cost and also has extort, I'm rather iffy on its effectiveness. I mean, it's only really good to stop creatures with haste. If I'm going against a deck without massive haste, it's probably not as effective, right? Or maybe I'd just main both and sideboard 1 or 2 copies of each, and then switch in round 2, depending on what I gathered from round 1? Or main one and sideboard the other?

The biggest issue I find with Desecration Demon is exactly that, but only when going against decks which can generate tokens or creatures with undying. I'll definitely keep some, since they're good to hit hard and also have a ton of defence - not to mention that it's always handy for an opponent to sacrifice against such a big creature, and with the Crypt Ghast s, they're really easy to cast. Maybe shove them to sideboard?

I'm also considering adding 2 more Beckon Apparition , at least to the sideboard. I don't know how the general meta is but, at my LGS, there's lots of people using the graveyard, mostly through flashback-able spells. I was also considering Grave Betrayal until recently to also defend myself against graveyard-heavy decks. But, well, I'm not sure that'd still be all that much of a good idea (besides, they don't have any of those at my local shop :/ ).

I'll definitely keep Barter in Blood and Mutilate in mind, though. Especially Mutilate, since it synergizes so well with Liliana of the Dark Realms . If I did have Grave Betrayal, though, it'd work very well with Mutilate, too. Something to keep in mind, I guess.

And completely forgot;One other thing I've learned this past couple days is that relying on such a mana-heavy spell probably isn't that much of a good idea. Stalling, even with the right tools, can be pretty hard, especially if my opponent has some counter-spell ready. So having any alternate way to put on some pressure would be nice. Maybe cutting down on Devour Flesh ? It's only really useful to set up a Tragic Slip or against very few creatures, or go against hexproofed creatures, but that doesn't seem like it'll be an issue if I ever add Mutilate or Barter in Blood.

Well the simple solution if they are casting/using the graveyard is to run some graveyard hate in the sideboard. Beckon Apparition is great but only removes a single card. You are already in white so how about Rest in Peace or if that doesnt tickle your fancy run some Grafdigger's Cage . About the removal, use the Devour Flesh early, dont let them have more then one or two creatures if you can help it. Not sure if you have Obzedat, Ghost Council or not but if so get him in this deck. From what I can see right now your win cons are either swing for the win or get off Debt to the Deathless its doable but like you said weak to counter decks. So maybe look for a few other win cons. Obezdat is almost a wincon on his own if he makes the table. You are likely to be making lots of mana so maybe look to extort using cheap spells and then a Pontiff of blight as a bomb to start really extorting.

Depending what you have for mana fixing you could always try adding another colour too. Blue goes with black white so well. Opens your deck to have counters, you can do things like Far / Away with it then. But it does require better mana fixing in a three colour deck.

Rest in Peace , got it. It's definitely a good choice for me. It's not all that cheap, though, but I'll just have to find a way to get a couple. That'd seriously secure most of my games. And even better, it can also stop decks with Undying, since creatures have to go to the graveyard before coming back. Even better, the CMC is really low, so it's very easily extortable.

Yeah, I'll have to keep that in mind about Devour Flesh . Usually I'm against someone with Undying and cards like Ooze Flux , Zameck Guildmage or Bioshift , though, so I never really have a chance to use it efficiently. But with Rest in Peace, that might start to be a viable solution.

Obzedat is a card I've been trying to get for some time, so I'll definitely add up to two whenever I get my hands on a couple of those.

Pontiff of Blight... maybe running 2 in my main would go well. I'll probably replace 2 Desecration Demons but, on the other hand, if I manage to disable things like Undying with Rest in Peace, Desecration Demons might start being useful. Unless my opponent likes playing with tokens. Maybe I'll just sideboard them, in case I find myself going against someone without tokens.

Going with three colours is a no deal for me, unfortunately. I mean, I'd love to, but stuff like shock lands is just out of question for me, right now. If I do manage to get a couple by some miracle, though, believe me - I'll definitely add a third colour, probably blue.

Currently considering changing this deck to the following Orzhov Test

check out Debt to the Pontiff. may give you some ideas, and i'd appreciate any comments you might have also. good luck.