Master of Waves — ruling 1

Use your devotion to blue as the triggered ability resolves to determine how many tokens are put onto the battlefield. If Master of Waves is still on the battlefield at that time, its mana cost will count toward your devotion to blue.

Master of Waves — ruling 2

Barring other effects, the Elemental tokens will enter the battlefield as 2/1 creatures.

Master of Waves — ruling 3

If Master of Waves leaves the battlefield, and nothing else is raising the toughness of the Elemental tokens above 0, the Elemental tokens will die and subsequently cease to exist.

Master of Waves — ruling 4

Numeric mana symbols ({0}, {1}, and so on) in mana costs of permanents you control don't count toward your devotion to any color.

Master of Waves — ruling 5

Mana symbols in the text boxes of permanents you control don't count toward your devotion to any color.

Master of Waves — ruling 6

Hybrid mana symbols, monocolored hybrid mana symbols, and Phyrexian mana symbols do count toward your devotion to their color(s).

Master of Waves — ruling 7

If an activated ability or triggered ability has an effect that depends on your devotion to a color, you count the number of mana symbols of that color among the mana costs of permanents you control as the ability resolves. The permanent with that ability will be counted if it's still on the battlefield at that time.

Master of Waves : règles, fonctionnement et interactions (MTG)

Master of Waves is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Protection from red Elemental creatures you control get +1/+1. When this creature enters, create a number of 1/0 blue Elemental creature tokens equal to your devotion to blue. (Each in the mana costs of permanents you control counts toward your devotion to blue.)

Complete guide

Master of Waves is a powerhouse in blue-based strategies, turning your accumulated mana symbols into a small army of Elemental tokens. As a Merfolk Wizard, it offers both a tribal boost and a scaling board presence that can overwhelm opponents in a single turn. With protection from red, it also serves as a resilient threat against aggressive burn spells and blockers.

Harnessing Devotion

Master of Waves features a triggered ability that checks your devotion to blue at the moment the ability resolves. Devotion is calculated by counting every blue mana symbol ({U}) in the mana costs of all permanents you control on the battlefield. This includes the {U} in the cost of Master of Waves itself if it is still present. Note that only mana symbols in the top-right corner (or equivalent for special frames) count; mana symbols mentioned in a card's text box do not contribute to devotion.

Resolution Step-by-Step

First, the Master of Waves enters the battlefield, triggering its ability. Second, players have a chance to respond with spells or abilities. Third, as the ability resolves, the game checks your current devotion to blue. Finally, you create that many 1/0 blue Elemental creature tokens. Because Master of Waves provides a static +1/+1 buff to Elementals, these tokens will enter the battlefield as 2/1 creatures as long as their master remains in play.

Fragile Armies and Common Pitfalls

The most important thing to remember is the dependency of the tokens on the Master. Since the Elemental tokens have a base toughness of 0, they rely entirely on the +1/+1 anthem effect to survive. If Master of Waves leaves the battlefield and no other effects (like Gaea's Anthem) are increasing their toughness, state-based actions will cause all the Elemental tokens to be put into the graveyard immediately. Also, remember that generic mana symbols like {1} or {3} do not contribute to devotion.

When to Play Master of Waves

Timing is crucial to maximize your token count. You generally want to cast this when you already have several permanents with blue mana symbols in play to ensure a high devotion count. Because it has protection from red, it is an excellent blocker against red creatures or a safe attacker against decks relying on Lightning Bolt for removal.

Interaction examples

Basic Token Generation

Elemental

If you control Master of Waves and no other blue permanents, your devotion to blue is 1. When the ability resolves, you create one 1/0 blue Elemental token. Because of the Master's static ability, that token becomes a 2/1 creature.

Artifacts and Devotion

Solemn Simulacrum

If you have Solemn Simulacrum and Master of Waves on the battlefield, your devotion to blue is still only 1. Since Solemn Simulacrum costs {4} and has no blue mana symbols in its cost, it does not contribute to the token count, though it remains a useful utility creature.

Doubling the Tide

Roaming Throne

If you have Roaming Throne on the battlefield and you chose 'Wizard' as it entered, Master of Waves's enters-the-battlefield ability will trigger twice. Each trigger will check your devotion separately as it resolves, potentially creating two large waves of Elemental tokens.

Guide written with AI from the official text and rulings. Official English text prevails.

How it works : Master of Waves

Original English text — Wizards of the Coast / Scryfall

#1September 15, 2013· Wizards of the Coast
Use your devotion to blue as the triggered ability resolves to determine how many tokens are put onto the battlefield. If Master of Waves is still on the battlefield at that time, its mana cost will count toward your devotion to blue.
No other card is named in this ruling.
#2September 15, 2013· Wizards of the Coast
Barring other effects, the Elemental tokens will enter the battlefield as 2/1 creatures.
Card named in this ruling
Elemental
#3September 15, 2013· Wizards of the Coast
If Master of Waves leaves the battlefield, and nothing else is raising the toughness of the Elemental tokens above 0, the Elemental tokens will die and subsequently cease to exist.
Card named in this ruling
Elemental
#4September 15, 2013· Wizards of the Coast
Numeric mana symbols (, , and so on) in mana costs of permanents you control don't count toward your devotion to any color.
No other card is named in this ruling.
#5September 15, 2013· Wizards of the Coast
Mana symbols in the text boxes of permanents you control don't count toward your devotion to any color.
No other card is named in this ruling.
#6September 15, 2013· Wizards of the Coast
Hybrid mana symbols, monocolored hybrid mana symbols, and Phyrexian mana symbols do count toward your devotion to their color(s).
No other card is named in this ruling.
#7September 15, 2013· Wizards of the Coast
If an activated ability or triggered ability has an effect that depends on your devotion to a color, you count the number of mana symbols of that color among the mana costs of permanents you control as the ability resolves. The permanent with that ability will be counted if it's still on the battlefield at that time.
No other card is named in this ruling.