The Balrog, Flame of Udûn

a Demon enters the battlefield — 284 cards in the game can cause this (The Balrog is one).

When The Balrog, Flame of Udûn enters:

1. Blood Speaker — returns itself from the graveyard
2. Be'lakor, the Dark Master — deals its power damage

a nontoken creature leaves the battlefield — 4,133 cards in the game can cause this (The Balrog is one).

When The Balrog, Flame of Udûn leaves the battlefield:

1. Tokka & Rahzar, Unsupervised — puts a +1/+1 counter on itself
2. Splinter, the Mentor — makes a token
3. Rat King, Pale Piper — makes a token
4. Dual Nature — exiles a creature

a creature leaves the battlefield — 4,238 cards in the game can cause this (The Balrog is one).

When The Balrog, Flame of Udûn leaves the battlefield:

1. Lunarch Veteran // Luminous Phantom — gains you 1 life
2. Extractor Demon — mills a card
3. Aang, Airbending Master — puts a counter on a permanent
4. Dour Port-Mage — draws you 1 card
5. Vela the Night-Clad — makes each opponent lose 1 life
6. Taeko, the Patient Avalanche — scries
7. Ninth Bridge Patrol — puts a +1/+1 counter on itself
8. Funeral March — makes a player sacrifice a creature
9. Sally Sparrow — triggers
10. Aang, at the Crossroads // Aang, Destined Savior — triggers

21 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 (The Balrog is one).

When The Balrog, Flame of Udûn attacks:

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

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 (The Balrog is one).

When The Balrog, Flame of Udûn 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. Jolene, Plundering Pugilist — makes a token
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

180 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 (The Balrog is one).

When The Balrog, Flame of Udûn blocks:

1. Mage Hunters' Onslaught — makes a player lose 1 life
2. Carnage Gladiator — makes a player lose 1 life
3. Barrow-Blade — strips abilities
4. Heat of Battle — deals 1 damage
5. Battle Strain — deals 1 damage
6. Favor of the Woods — gains you 3 life
7. Tide of War — sacrifices a creature
8. Dead-Iron Sledge — kills a creature
9. Dwindle — kills a creature
10. Shield of the Righteous — triggers

18 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 (The Balrog is one).

When The Balrog, Flame of Udûn attacks:

1. Mardu Ascendancy — makes a token
2. Basri Ket — makes a token
3. Militia's Pride — makes a token

a creature deals combat damage — 17,934 cards in the game can cause this (The Balrog is one).

1. Tifa, Martial Artist — When The Balrog, Flame of Udûn deals combat damage, Tifa, Martial Artist untaps a permanent

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

a creature is cast — 18,010 cards in the game can cause this (The Balrog is one).

1. Champions of the Perfect — When The Balrog, Flame of Udûn is cast, Champions of the Perfect draws you 1 card

90 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 (The Balrog is one).

When The Balrog, Flame of Udûn 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

297 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 (The Balrog is one).

1. Prowl, Stoic Strategist // Prowl, Pursuit Vehicle — When The Balrog, Flame of Udûn enters, Prowl, Stoic Strategist // Prowl, Pursuit Vehicle puts a +1/+1 counter on itself

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