Sengir, the Dark Baron

Flying
Whenever another creature dies, put two +1/+1 counters on Sengir, the Dark Baron.
Whenever another player loses the game, you gain life equal to that player's life total as the turn began.
Partner (You can have two commanders if both have partner.)

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Commander's Plate

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander {3}
Equip {5}

Dark Ritual

Terror

Destroy target nonartifact, nonblack creature. It can't be regenerated.

Diabolic Edict

Mana Vault

Mana Vault doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {4}. If you do, untap Mana Vault.
At the beginning of your draw step, if Mana Vault is tapped, it deals 1 damage to you.
{T}: Add {C}{C}{C}.

Drain Life

Spend only black mana on X.
Drain Life deals X damage to any target. You gain life equal to the damage dealt, but not more life than the player's life total before the damage was dealt, the planeswalker's loyalty before the damage was dealt, or the creature's toughness.

Seal of Doom

Sacrifice Seal of Doom: Destroy target nonblack creature. It can't be regenerated.

Skulking Fugitive

When Skulking Fugitive becomes the target of a spell or ability, sacrifice it.

Prismatic Lens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Fatal Blow

Destroy target creature that was dealt damage this turn. It can't be regenerated.

Mind Swords

If you control a Swamp, you may sacrifice a creature rather than pay this spell's mana cost.
Each player exiles two cards from their hand.

Burning-Rune Demon

Flying
When Burning-Rune Demon enters the battlefield, you may search your library for exactly two cards not named Burning-Rune Demon that have different names. If you do, reveal those cards. An opponent chooses one of them. Put the chosen card into your hand and the other into your graveyard, then shuffle.

Feast of Succession

All creatures get -4/-4 until end of turn. You become the monarch.

Vampiric Embrace

Enchant creature
Enchanted creature gets +2/+2 and has flying.
Whenever a creature dealt damage by enchanted creature this turn dies, put a +1/+1 counter on that creature.

Ashen Powder

Put target creature card from an opponent's graveyard onto the battlefield under your control.

Swamp

Evincar's Justice

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Evincar's Justice deals 2 damage to each creature and each player.

Stronghold Assassin

{T}, Sacrifice a creature: Destroy target nonblack creature.

Raise Dead

Return target creature card from your graveyard to your hand.

Mindstab Thrull

Whenever Mindstab Thrull attacks and isn't blocked, you may sacrifice it. If you do, defending player discards three cards.

Epic Downfall

Exile target creature with mana value 3 or greater.

Soul Channeling

Enchant creature
Pay 2 life: Regenerate enchanted creature.

Ashes to Ashes

Exile two target nonartifact creatures. Ashes to Ashes deals 5 damage to you.

Expunge

Destroy target nonartifact, nonblack creature. It can't be regenerated.
Cycling {2} ({2}, Discard this card: Draw a card.)

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

No Rest for the Wicked

Sacrifice No Rest for the Wicked: Return to your hand all creature cards in your graveyard that were put there from the battlefield this turn.

Cloak of Confusion

Enchant creature you control
Whenever enchanted creature attacks and isn't blocked, you may have it assign no combat damage this turn. If you do, defending player discards a card at random.

Sol Ring

Cremate

Exile target card from a graveyard.
Draw a card.

Necrite

Whenever Necrite attacks and isn't blocked, you may sacrifice it. If you do, destroy target creature defending player controls. It can't be regenerated.

Blood Pet

Ghastly Demise

Destroy target nonblack creature if its toughness is less than or equal to the number of cards in your graveyard.

Disentomb

Dark Tutelage

At the beginning of your upkeep, reveal the top card of your library and put that card into your hand. You lose life equal to its mana value.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Plague Dogs

When Plague Dogs dies, all creatures get -1/-1 until end of turn.
{2}, Sacrifice Plague Dogs: Draw a card.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Blood Vassal

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Command Tower

Tevesh Szat, Doom of Fools

+2: Create two 0/1 black Thrull creature tokens.
+1: You may sacrifice another creature or planeswalker. If you do, draw two cards, then draw another card if the sacrificed permanent was a commander.
−10: Gain control of all commanders. Put all commanders from the command zone onto the battlefield under your control.
Tevesh Szat, Doom of Fools can be your commander.
Partner

Dark Banishing

Destroy target nonblack creature. It can't be regenerated.

Phyrexian Reclamation

{1}{B}, Pay 2 life: Return target creature card from your graveyard to your hand.

Mortuary

Whenever a creature is put into your graveyard from the battlefield, put that card on top of your library.

Oath of Liliana

When Oath of Liliana enters the battlefield, each opponent sacrifices a creature.
At the beginning of each end step, if a planeswalker entered the battlefield under your control this turn, create a 2/2 black Zombie creature token.

Extinction

Destroy all creatures of the creature type of your choice.

Sengir Autocrat

When Sengir Autocrat enters the battlefield, create three 0/1 black Serf creature tokens.
When Sengir Autocrat leaves the battlefield, exile all Serf tokens.

Arrogant Outlaw

When Arrogant Outlaw enters the battlefield, if an opponent lost life this turn, each opponent loses 2 life and you gain 2 life.

Minion of the Wastes

Trample
As Minion of the Wastes enters the battlefield, pay any amount of life.
Minion of the Wastes's power and toughness are each equal to the life paid as it entered the battlefield.

Pestilence

At the beginning of the end step, if no creatures are on the battlefield, sacrifice Pestilence.
{B}: Pestilence deals 1 damage to each creature and each player.

Sadistic Glee

Enchant creature
Whenever a creature dies, put a +1/+1 counter on enchanted creature.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}