Viper, Cruel Conspirator

an Assassin deals combat damage — 212 cards in the game can cause this (Viper is one).

When Viper, Cruel Conspirator deals combat damage:

1. Layla Hassan — brings a card back
2. Ezio, Blade of Vengeance — draws you 1 card
3. Etrata, Deadly Fugitive — triggers
4. Jacob Frye — exiles a card from your graveyard

an Assassin attacks — 212 cards in the game can cause this (Viper is one).

When Viper, Cruel Conspirator attacks:

1. The Revelations of Ezio — puts a counter on a permanent
2. Origin of the Hidden Ones — makes a token

an Assassin creature it grants types to — 219 cards in the game can cause this.

1. Reaper's Scythe — Reaper's Scythe gives Viper, Cruel Conspirator an extra creature type

218 other cards cause it too. These are the ones with the most connections.

a Villain deals combat damage — 255 cards in the game can cause this (Viper is one).

When Viper, Cruel Conspirator deals combat damage:

1. Loki, the Deceiver — draws you 1 card
2. Stilt-Man, Towering Terror — triggers

1 other card cares about it too. These are the ones with the most connections.

a Villain enters the battlefield — 268 cards in the game can cause this (Viper is one).

When Viper, Cruel Conspirator enters:

1. Flying Octobot — puts a +1/+1 counter on itself
2. Doom Reigns Supreme — makes each opponent lose 1 life
3. Crossbones, Malicious Mercenary — puts a +1/+1 counter on itself
4. Yellowjacket, Heartless Marauder — gets +1/+0
5. Swordsman, Sharp Scoundrel — triggers
6. Prowler, Clawed Thief — draws and discards
7. Baron Strucker, HYDRA Overlord — draws and discards

a Human enters the battlefield — 4,639 cards in the game can cause this (Viper is one).

When Viper, Cruel Conspirator enters:

1. General Kudro of Drannith — hits a graveyard
2. Heronblade Elite — puts a +1/+1 counter on itself
3. Kyler, Sigardian Emissary — puts a +1/+1 counter on itself
4. Thalia's Lieutenant — puts a +1/+1 counter on itself
5. Champion of the Parish — puts a +1/+1 counter on itself
6. Captain of the Mists — untaps itself
7. Erkenbrand, Lord of Westfold — gives +1/+0
8. Beregond of the Guard — gives +1/+1
9. Théoden, King of Rohan — grants double strike
10. Lossarnach Captain — taps a creature an opponent controls

2 other cards care about it too. These are the ones with the most connections.

anything attacks — 17,934 cards in the game can cause this (Viper is one).

When Viper, Cruel Conspirator attacks:

1. Far Fortune, End Boss — deals 1 damage
2. Temmet, Naktamun's Will — draws you 1 card
3. Grim Javelineer — gives +1/+0
4. Invisible Woman — triggers
5. Caesar, Legion's Emperor — sacrifices a creature
6. Guide of Souls — triggers
7. Campsite Cuisine — sacrifices a Food
8. Gossip's Talent — triggers
9. Banon, the Returners' Leader — draws and discards
10. Toph, Earthbending Master — puts a counter on a permanent

112 other cards care about it too. These are the ones with the most connections.

a creature attacks — 17,934 cards in the game can cause this (Viper is one).

When Viper, Cruel Conspirator attacks:

1. Adaptive Omnitool — searches a library
2. Anthem of Rakdos — gives +2/+0
3. Kindred Discovery — draws you 1 card
4. Invasion of New Capenna // Holy Frazzle-Cannon — puts counters on a permanent
5. Chorale of the Void — brings a card back
6. Anim Pakal, Thousandth Moon — puts a +1/+1 counter on itself
7. Saw — sacrifices a creature
8. Gisa's Favorite Shovel — makes an opponent sacrifice a creature
9. Ultima Weapon — kills a creature an opponent controls
10. Total War — kills a creature

181 other cards care about it too. These are the ones with the most connections.

a creature blocks — 17,934 cards in the game can cause this (Viper is one).

When Viper, Cruel Conspirator blocks:

1. Mage Hunters' Onslaught — makes a player lose 1 life
2. Carnage Gladiator — makes a player lose 1 life
3. Tide of War — sacrifices a creature
4. Dead-Iron Sledge — kills a creature
5. Dwindle — kills a creature

23 other cards care about it too. These are the ones with the most connections.

a nontoken creature attacks — 17,934 cards in the game can cause this (Viper is one).

1. Mardu Ascendancy — When Viper, Cruel Conspirator attacks, Mardu Ascendancy makes a token

2 other cards care about it too. These are the ones with the most connections.

a creature enters the battlefield — 19,800 cards in the game can cause this (Viper is one).

When Viper, Cruel Conspirator enters:

1. Slash, Reptile Rampager — deals 2 damage
2. Gimli of the Glittering Caves — puts counters on a permanent
3. Ray Fillet, Wave Warrior — puts a counter on itself
4. Legolas Greenleaf — puts a counter on a permanent
5. The Neutrinos — gets +1/+0
6. Wingnut, Bat on the Belfry — grants flying, haste and menace
7. Aetherstorm Roc — puts a counter on a permanent you control
8. Raphael, Most Attitude — exiles a card from your library

300 other cards care about it too. These are the ones with the most connections.

anything enters the battlefield — 26,499 cards in the game can cause this (Viper is one).

1. Prowl, Stoic Strategist // Prowl, Pursuit Vehicle — When Viper, Cruel Conspirator enters, Prowl, Stoic Strategist // Prowl, Pursuit Vehicle puts a +1/+1 counter on itself

44 other cards care about it too. These are the ones with the most connections.