[cEDH] Yawgmoth's undying engine (EDH / Commander)

How to play

This adaptable Yawgmoth build is capable of controlling the board and shutting down creature-based strategies while generating value doing so. At the same time, the deck is designed to win the game in explosive turnes out of nowhere, making it a mixture of a control and storm build.

The Lord of the Wastes himself serves excelent as a board control and carddraw engine til we draw into combo pieces or tutors. Heavy carddraw in combination with fast mana and mana positive rocks allows us to win all at once while cards like Duress or Imp's Mischief protect us when we're ready to combo off.

What to tutor for?

Entomb will find Bridge from Below most of the time to assemble your Undying combo.
Final Parting will put Bridge from Below in your graveyard and an undying creature in hand most of the time
If you already control Sensei's Divining Top or Bolas's Citadel it's a good idea to tutor for the corresponding other.
If you already control Necropotence it's good idea to tutor for Bolas's Citadel.

Win Conditions:

The Undying Win

(Rulings: Putting a +1/+1 counter on a creature with a -1/-1 counter will remove both.

704.5r: If a permanent has both a +1/+1 counter and a -1/-1 counter on it, N +1/+1 and N -1/-1 counters are removed from it, where N is the smaller of the number of +1/+1 and -1/-1 counters on it.)

Butcher Ghoul, Geralf's Messenger, Sightless Ghoul or Evernight Shade + another Undying Creature + Yawgmoth, Thran Physician + Zulaport Cutthroat or Bastion of Remembrance
-> Draw whole deck and kill opponents due to loss of life (with 40 or more cards in your library)

Undying Creature or Treacherous Pit-Dweller + Pawn of Ulamog or Genesis Chamber or Bridge from Below in Graveyard or Nest of Scarabs(and one more creature on the battlefield) + Yawgmoth, Thran Physician + Zulaport Cutthroat or Bastion of Remembrance
-> same effect

Geralf's Messenger + another Undying Creature or one of the 4 substitutes + Yawgmoth, Thran Physician + Deathgreeter
-> same effect (with 60 or more cards in your library)

Note:
This build is optimized to start comboing off without an outlet like Zulaport Cutthroat on the battlefield as long as Treacherous Pit-Dweller isn't the Undying creature in the combo. Even with 0 mana left this deck is able to chain fast mana to cast an outlet or a tutor to find it on our way through the deck.

Backup Plans:

Enchantments like Rest in Peace or Leyline of the Void are the worst nightmares of this deck. Therefore we need ways to win without abusing aristocrat and graveyard strategies...

Bolas's Citadel Storm

Bolas's Citadel + Aetherflux Reservoir + Sensei's Divining Top
-> Repeatedly use Sensei's Divining Top activated ability to put it on top of your library and cast it for one life with Bolas's Citadel triggering Aetherflux Reservoir each time. Then use Aetherflux Reservoirs activated ability 3 times.
-> Most of the time you can start comboing off with just Citadel and Top paying one life per card till you run into Aetherflux or created enough value
-> You can use Insidious Dreams in your opponent's end step if you have 3 more cards in hand and 6 mana available in your turn to win out of nowhere

Single Card Discussion

Evernight Shade and Sightless Ghoul -> These cards are obviously very expensive but have proven themselves in practice as the deck can easily generate a lot of mana

Phyrexian Revoker -> A card which is not mandatory depending on the meta, but which can be used very flexible, because unlike cards like Pithing Needle it can also deactivate mana abilities. Furthermore it is more synergetic as a creature in the deck and can be sacrificed in Skullclamp.

Why some cards are not played

More substitutes like Desecrated Tomb, Sifter of Skulls etc.
-> You could include this card and more substitutes, but in my experience it's not worth it because you'll end up with dead cards like two substitutes in your hand.

Necromancy and Dance of the Dead
-> One could optimise the deck more in the direction of reanimator, but in my opinion this has not been worthwhile so far. For one thing, Yawgmoth's discard ability is much too expensive. On the other hand Entomb usually finds Bridge from Below anyway. Therefore I only play two reanimator spells.

"Final" Version of this deck: https://www.moxfield.com/decks/k9qgc4pNrE6R9E1dD5Ih3g

Leyline of the Void is only here because of my current meta. In an more control heavy meta I'd use Conqueror's Flail and more hand control such as Inquisition of Kozilek

Treacherous Pit-Dweller rulings
Due to it's ETB Treacherous Pit-Dweller can only be used with one of the 4 substitutes, because it's ETB resolves before Yawg's activated ability.

Example with Butcher Ghoul and Treacherous Pit-Dweller:

We activate Yawg, target enemy or none creature, sacrificing Treacherous Pit-Dweller (TPD)
-> Stack: Bottom - Yawg's activated ability; Top - TPD's Undying trigger -> Let TPD's Undying trigger resolve

TPD is returned with the +1/+1 counter. Treacherous Pit-Dweller's control-change ability triggers.
-> Stack: Bottom - Yawg's activated ability; Top - TPD's control-change trigger

We activate Yawg, target TPD, sacrificing Butcher Ghoul
-> Stack: Bottom - Yawg's activated ability; Above - TPD's control-change trigger; Above - Yawg's activated ability; Top - Butcher Ghoul's Undying trigger -> Let Butcher Ghoul's Undying trigger resolve -> Let Yawg's activated ability resolve

Butcher Ghoul is returned with the +1/+1 counter and TPD loses it's +1/+1 counter

We activate Yawg, target Butcher Ghoul, sacrificing Treacherous Pit-Dweller (TPD)

-> Stack: Bottom - Yawg's activated ability; Above - TPD's control-change trigger; Above - Yawg's activated ability; Top - TPD's Undying trigger -> Let TPD's Undying trigger resolve

TPD is returned with the +1/+1 counter. Treacherous Pit-Dweller's control-change ability triggers.

-> At this point we would need to sacrifice Butcher Ghoul but both Undying creatures have a +1/+1 counter and the combo stops

Example with Treacherous Pit-Dweller and Pawn of Ulamog:

We activate Yawg, target enemy or none creature, sacrificing Treacherous Pit-Dweller (TPD)
-> Stack: Bottom - Yawg's activated ability; Top - TPD's Undying trigger + Pawn of Ulamog's trigger -> We let TPD's Undying trigger and Pawn of Ulamog's trigger resolve

TPD is returned with the +1/+1 counter and a Eldrazi Token is created. Treacherous Pit-Dweller's control-change ability triggers.
-> Stack: Bottom - Yawg's activated ability; Top - TPD's control-change trigger

We activate Yawg, target TPD, sacrificing the Eldrazi Token
-> Stack: Bottom - Yawg's activated ability; Above - TPD's control-change trigger; Top - Yawg's activated ability

Yawg's activated ability resolves, we put the -1/-1 counter on TPD and draw a card.
-> Stack: Bottom - Yawg's activated ability; Top - TPD's control-change trigger

We activate Yawg, target enemy or none creature, sacrificing Treacherous Pit-Dweller (TPD)
-> Stack: Bottom - Yawg's activated ability; Above - TPD's control-change trigger; Above - Yawg's activated ability; Top - TPD's Undying trigger + Pawn of Ulamog's trigger

-> At this point we can just go on and win on the stack leaving another Yawg activation and TPD control-change trigger on the stack each time