Cruel Sadist

{B}, {T}, Pay 1 life: Put a +1/+1 counter on Cruel Sadist.
{2}{B}, {T}, Remove X +1/+1 counters from Cruel Sadist: It deals X damage to target creature.

Thorn of the Black Rose

Deathtouch
When Thorn of the Black Rose enters, you become the monarch.

Raffine's Silencer

When Raffine's Silencer enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)
When Raffine's Silencer dies, target creature an opponent controls gets -X/-X until end of turn, where X is Raffine's Silencer's power.

Hired Poisoner

Gixian Skullflayer

At the beginning of your upkeep, if there are three or more creature cards in your graveyard, put a +1/+1 counter on Gixian Skullflayer.

Etrata, the Silencer

Etrata, the Silencer can't be blocked.
Whenever Etrata deals combat damage to a player, exile target creature that player controls and put a hit counter on that card. That player loses the game if they own three or more exiled cards with hit counters on them. Etrata's owner shuffles Etrata into their library.

Royal Assassin

Tsabo's Assassin

{T}: Destroy target creature if it shares a color with the most common color among all permanents or a color tied for most common. A creature destroyed this way can't be regenerated.

Silumgar Assassin

Creatures with power greater than Silumgar Assassin's power can't block it.
Megamorph {2}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When Silumgar Assassin is turned face up, destroy target creature with power 3 or less an opponent controls.

Big Game Hunter

When Big Game Hunter enters, destroy target creature with power 4 or greater. It can't be regenerated.
Madness {B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Ramses, Assassin Lord

Deathtouch
Other Assassins you control get +1/+1.
Whenever a player loses the game, if they were attacked this turn by an Assassin you controlled, you win the game.

Hunter of Eyeblights

When Hunter of Eyeblights enters, put a +1/+1 counter on target creature you don't control.
{2}{B}, {T}: Destroy target creature with a counter on it.

Vorpal Sword

Equipped creature gets +2/+0 and has deathtouch.
{5}{B}{B}{B}: Until end of turn, Vorpal Sword gains "Whenever equipped creature deals combat damage to a player, that player loses the game."
Equip {B}{B}

Dark Impostor

{4}{B}{B}: Exile target creature and put a +1/+1 counter on Dark Impostor.
Dark Impostor has all activated abilities of all creature cards exiled with it.

Eyeblight Assassin

When Eyeblight Assassin enters, target creature an opponent controls gets -1/-1 until end of turn.

Hooded Assassin

When Hooded Assassin enters, choose one —
• Put a +1/+1 counter on Hooded Assassin.
• Destroy target creature that was dealt damage this turn.

Undercity Eliminator

When Undercity Eliminator enters, you may sacrifice an artifact or creature. When you do, exile target creature an opponent controls.

Guildsworn Prowler

Deathtouch
When Guildsworn Prowler dies, if it wasn't blocking, draw a card.

Massacre Girl

Menace
When Massacre Girl enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies this turn, each creature other than Massacre Girl gets -1/-1 until end of turn.

Midnight Assassin

Flying
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Unliving Psychopath

{B}: Unliving Psychopath gets +1/-1 until end of turn.
{B}, {T}: Destroy target creature with power less than Unliving Psychopath's power.

Final-Sting Faerie

Flying
When Final-Sting Faerie enters, destroy target creature that was dealt damage this turn.

Blood Operative

Lifelink
When Blood Operative enters, you may exile target card from a graveyard.
Whenever you surveil, if Blood Operative is in your graveyard, you may pay 3 life. If you do, return Blood Operative to your hand.

Vraska's Finisher

When Vraska's Finisher enters, destroy target creature or planeswalker an opponent controls that was dealt damage this turn.

Lurking Deadeye

Flash
When Lurking Deadeye enters, destroy target creature that was dealt damage this turn.

Nightshade Assassin

First strike
When Nightshade Assassin enters, you may reveal X black cards in your hand. If you do, target creature gets -X/-X until end of turn.
Madness {1}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Stingblade Assassin

Flash
Flying
When Stingblade Assassin enters, destroy target creature an opponent controls that was dealt damage this turn.

Stalking Assassin

{3}{U}, {T}: Tap target creature.
{3}{B}, {T}: Destroy target tapped creature.

Skulking Killer

When Skulking Killer enters, target creature an opponent controls gets -2/-2 until end of turn if that opponent controls no other creatures.

Orzhov Euthanist

Haunt (When this creature dies, exile it haunting target creature.)
When Orzhov Euthanist enters or the creature it haunts dies, destroy target creature that was dealt damage this turn.