Roku's Mastery

you scry — 420 cards in the game can cause this (Roku's Mastery is one).

When Roku's Mastery scries:

1. Prudent Fateseer // Peer Review — gives +1/+0
2. Diviner of Victory // Unwind History — gets +1/+1
3. Saheeli, Consul of Oversight — makes a token
4. Celeborn the Wise — makes your creatures bigger
5. Proft, Consulting Detective — puts a +1/+1 counter on itself
6. Matoya, Archon Elder — draws you 1 card
7. Denzilore Fatehold — puts a counter on a creature
8. Elminster — costs less
9. Elrond, Master of Healing — puts a counter on a creature
10. Galadriel of Lothlórien — puts a land onto the battlefield

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

anything deals noncombat damage — 3,068 cards in the game can cause this (Roku's Mastery is one).

When Roku's Mastery deals noncombat damage:

1. Quest for Pure Flame — puts a quest counter on itself
2. Soul-Scar Mage — puts that many counters on a permanent
3. Fear of Burning Alive — deals that amount damage
4. Niv-Mizzet, Visionary — draws you that many cards
5. Chandra's Incinerator — deals that much damage
6. Chandra's Pyreling — gets +1/+0
7. Talon of Pain — puts a charge counter on itself
8. Asgardian Inspiration — returns itself from the graveyard
9. Thor, Guardian of Midgard — exiles a card from your library
10. Virtue of Courage // Embereth Blaze — exiles a card from your library

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

an instant is cast — 3,931 cards in the game can cause this (Roku's Mastery is one).

When Roku's Mastery is cast:

1. Tomik, Izzet Sparkmage — gets +1/+1
2. Tor Wauki the Younger — deals 2 damage
3. Lunar Mystic — draws you 1 card
4. Ojer Pakpatiq, Deepest Epoch // Temple of Cyclical Time — grants rebound
5. Repeated Reverberation — copies an ability
6. Riku of Two Reflections — copies a spell
7. Sword of Wealth and Power — copies a spell
8. Lilah, Undefeated Slickshot — gets +1/+1
9. Artist's Talent — draws and discards
10. In the Eye of Chaos — counters a spell

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

a creature is dealt damage — 18,923 cards in the game can cause this (Roku's Mastery is one).

When a creature is dealt damage thanks to Roku's Mastery:

1. Soul Link — gains you that much life
2. Shriveling Rot — kills it
3. Cryoshatter — kills a creature
4. Hot Soup — kills a creature
5. Cracked Skull — kills a creature
6. Sporogenic Infection — kills a creature
7. Frozen Solid — kills a creature
8. Mortal Wound — kills a creature
9. Mire Blight — kills it
10. Death Pits of Rath — kills it

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

anything is cast — 31,128 cards in the game can cause this (Roku's Mastery is one).

When Roku's Mastery is cast:

1. Windrider Wizard — draws you 1 card
2. Relic Amulet — puts a charge counter on itself
3. Rockslide Sorcerer — deals 1 damage
4. Umara Wizard // Umara Skyfalls — grants flying
5. Alania, Divergent Storm — makes an opponent draw 1 card
6. Umara Mystic — gets +2/+0
7. Master of Winds — triggers

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