Helm/Void

[remoramistica]

Hello, I´m willing to know if you consider that this combo is viable as maindeck win condition for this particular monoblack build:

Combo:
4 Helm of Obedience
4 Leyline of the Void
4 Serum Powder

Card Advantage:
1 Necropotence
1 Yawgmoth´s Bargain
1 Yawgmoth´s Will
4 Infernal Contract
4 Street Wraith

Tutor:
1 Demonic Consultation
1 Demonic Tutor
1 Vampiric Tutor

Mana:
1 Black Lotus
1 Mox Jet
1 Sol Ring
1 Mana Crypt
1 Mana Vault
1 Lion´s Eye Diamond
1 Lotus Petal
4 Dark Ritual
3 Chrome Mox

Protection:
4 Duress
2 Thoughtsieze

Lands:
2 City of Traitors
2 Ancient Tomb
4 Polluted Delta
6 Swamps

Do you think that it is competitive enough?
How should I improve it?

Thanks

[Killane]

Hello, I´m willing to know if you consider that this combo is viable as maindeck win condition for this particular monoblack build:

Combo:
4 Helm of Obedience
4 Leyline of the Void
4 Serum Powder

Card Advantage:
1 Necropotence
1 Yawgmoth´s Bargain
1 Yawgmoth´s Will
4 Infernal Contract
4 Street Wraith

Tutor:
1 Demonic Consultation
1 Demonic Tutor
1 Vampiric Tutor

Mana:
1 Black Lotus
1 Mox Jet
1 Sol Ring
1 Mana Crypt
1 Mana Vault
1 Lion´s Eye Diamond
1 Lotus Petal
4 Dark Ritual
3 Chrome Mox

Protection:
4 Duress
2 Thoughtsieze

Lands:
2 City of Traitors
2 Ancient Tomb
4 Polluted Delta
6 Swamps

Do you think that it is competitive enough?
How should I improve it?

Thanks

Off the top, how do you handle this:

your opponent, on the play, goes

Land, Mox, Null Rod.

you have no way to remove the Rod, and no win other than beating with Street Wraiths (which, given that you're likely play against Fish or Null Oath is not going to happen).

This would be a less relevant question except that null Rod is alredy widely played due to the presence of Tezz in the format.

speaking of which, Vault + Key is also a two card instant win that is less color-intensive, less mana-intensive, and fits in a mush more controlling shell.

or

Tendrils fits in the Storm-ish shell that you have created, with big draw spells, fast mana, and YawgWin, and is less vulnerable to counterspells and doesn't fold to Null Rod.

Why not go one of those ways?

[Beralt]

Adding a touch of Blue with Underground Seas (since you are already running Fetches) & Sapphire Mox (in place of a Chrome), allows you to run Ancestral, Time Walk, Tinker and some form of Blue Bounce - Hurkyls, Repeal, Rebuild, Echoing Truth, Chain of Vapor etc.  This might solve your Null Rod dilemma.

[remoramistica]

Thanks to both for that quick response.

I am aware of the Null Rod problem and I was guessing if maybie the new Sadistic Sacrament could help by making it harder to cast (and it is just marvelous against many other decks). I could replace the wraiths for it but I am not sure on how will that affect the heavily combo orientation of a deck that really needs to be thinner.
 
I`m currently running three tendrils at the sideboard. I believe that I should play at least one in main, thanks for the advice.

[Killane]

Thanks to both for that quick response.

I am aware of the Null Rod problem and I was guessing if maybie the new Sadistic Sacrament could help by making it harder to cast (and it is just marvelous against many other decks). I could replace the wraiths for it but I am not sure on how will that affect the heavily combo orientation of a deck that really needs to be thinner.
 
I`m currently running three tendrils at the sideboard. I believe that I should play at least one in main, thanks for the advice.

A maindeck Tendrils shoudl help a great deal. In fact, I'd wager it will win you more games than the "main" combo in the current meta.

Sacrament sounds nice, but if i was facing you I'd most likely mull aggressively into a Null Rod in my opener (which will often be cast on turn 1). I think in the end if you want to rely on Artifact win conditions you'll need to splash another color to deal with the rod.

I'm never quite sure why folks are wanting to run a mono-anything deck in Vintage- after dozens of sets of mana-fixing, you can pretty mush splash whatever you want, and run two or three colors without being TOO screwed by Wastelands.