Eidolon of Countless Battles

a nontoken Spirit deals combat damage — 725 cards in the game can cause this (Eidolon of Countless Battles is one).

1. Millicent, Restless Revenant — When Eidolon of Countless Battles deals combat damage, Millicent, Restless Revenant makes a token

a nontoken Spirit enters the battlefield — 727 cards in the game can cause this (Eidolon of Countless Battles is one).

1. Baboon Spirit — When Eidolon of Countless Battles enters, Baboon Spirit makes a token

a Spirit enters the battlefield — 863 cards in the game can cause this (Eidolon of Countless Battles is one).

When Eidolon of Countless Battles enters:

1. Mausoleum Wanderer — gets +1/+1
2. Drogskol Cavalry — gains you 2 life
3. Vanguard of the Restless — returns itself from the graveyard
4. Nebelgast Herald — taps a creature an opponent controls

an enchantment is cast — 3,673 cards in the game can cause this (Eidolon of Countless Battles is one).

When Eidolon of Countless Battles is cast:

1. Hallowed Haunting — makes a token
2. Daxos the Returned — puts a counter on a permanent
3. Tatsunari, Toad Rider — makes a token
4. Sythis, Harvest's Hand — gains you 1 life
5. Sigil of the Empty Throne — makes a token
6. Dawnhart Geist — gains you 2 life
7. Herald of the Pantheon — gains you 1 life
8. Kami of Transience — puts a +1/+1 counter on itself
9. Argothian Enchantress — draws you 1 card
10. Mesa Enchantress — draws you 1 card

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

a nontoken enchantment enters the battlefield — 3,691 cards in the game can cause this (Eidolon of Countless Battles is one).

1. Historian's Boon — When Eidolon of Countless Battles enters, Historian's Boon makes a token

an enchantment enters the battlefield — 3,743 cards in the game can cause this (Eidolon of Countless Battles is one).

When Eidolon of Countless Battles enters:

1. Calix, Guided by Fate — puts a counter on a creature
2. Elvish Archivist — draws you 1 card
3. Victor, Valgavoth's Seneschal — surveils
4. Strength from the Fallen — gives +X/+X, where X is the number of creature cards in your graveyard
5. Doomwake Giant — shrinks a creature by -1/-1
6. Cacophony Unleashed — turns something into a creature
7. Ghostly Dancers — makes a token
8. Thassa's Devourer — mills a card
9. Killian, Decisive Mentor — taps a creature
10. Thoughtrender Lamia — makes an opponent discard a card

67 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 (Eidolon of Countless Battles is one).

When Eidolon of Countless Battles attacks:

1. Within Range — makes each opponent lose life
2. Sparring Regimen — puts a counter on a creature
3. Far Fortune, End Boss — deals 1 damage
4. Temmet, Naktamun's Will — draws you 1 card
5. Campsite Cuisine — sacrifices a Food
6. Obsessive Pursuit — makes you lose life
7. Invisible Woman — triggers
8. Caesar, Legion's Emperor — sacrifices a creature
9. Guide of Souls — triggers
10. Gossip's Talent — triggers

116 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 (Eidolon of Countless Battles is one).

When Eidolon of Countless Battles 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

182 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 (Eidolon of Countless Battles is one).

When Eidolon of Countless Battles blocks:

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

24 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 (Eidolon of Countless Battles is one).

When Eidolon of Countless Battles is cast:

1. Primeval Bounty — makes a token
2. Communal Brewing — it arrives with counters thanks to Communal Brewing

89 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 (Eidolon of Countless Battles is one).

When Eidolon of Countless Battles enters:

1. Airbender Ascension — puts a quest counter on itself
2. Slash, Reptile Rampager — deals 2 damage
3. The Neutrinos — gets +1/+0
4. Wingnut, Bat on the Belfry — grants flying, haste and menace
5. Aetherstorm Roc — puts a counter on a permanent you control
6. Raphael, Most Attitude — exiles a card from your library

331 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 (Eidolon of Countless Battles is one).

1. Prowl, Stoic Strategist // Prowl, Pursuit Vehicle — When Eidolon of Countless Battles enters, Prowl, Stoic Strategist // Prowl, Pursuit Vehicle puts a +1/+1 counter on itself

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