Magus of the Moon — ruling 1

If a nonbasic land has an ability that triggers "when" it enters the battlefield, it will lose that ability before it can trigger.

Magus of the Moon — ruling 2

If a nonbasic land has an ability that causes it to enter the battlefield tapped, it will lose that ability before it can apply. The same is also true of any other abilities that modify how a land enters the battlefield or apply "as" a land enters the battlefield, such as that of Vesuva or Cavern of Souls.

Magus of the Moon — ruling 3

Nonbasic lands lose any other land types and abilities they had. They gain the land type Mountain and gain the ability "{T}: Add {R}."

Magus of the Moon — ruling 4

Magus of the Moon doesn't affect names or supertypes. It won't turn any land into a basic land or remove the legendary supertype from a legendary land, and the lands won't be named "Mountain."

Magus of the Moon — ruling 5

If Magus of the Moon loses its abilities, it continues to turn nonbasic lands into Mountains. This is because effects that change subtypes are applied before considering effects that remove abilities, regardless of the order in which those effects started.

Magus of the Moon : règles, fonctionnement et interactions (MTG)

Magus of the Moon 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

Nonbasic lands are Mountains.

Complete guide

Magus of the Moon is a powerful creature that brings the fiery dominance of the moon to the battlefield, stripping complex landscapes of their power. By turning every nonbasic land into a simple Mountain, it can completely disrupt an opponent's mana base or utility land strategy. Understanding its layers and timing is essential for mastering this classic red hate-piece.

What Magus of the Moon Does

Magus of the Moon possesses a continuous effect that changes the land type of all nonbasic lands to Mountain. While under this effect, these lands lose all their original printed abilities and land types, gaining only the ability to tap for red mana. It is important to note that it does not change the land's name or its supertypes; a legendary land remains legendary, and a nonbasic land remains nonbasic, even though it is now a Mountain.

Step-by-Step Resolution

When Magus of the Moon enters the battlefield, its effect applies immediately. First, the game identifies all lands that do not have the 'Basic' supertype. Second, these lands lose all other land types (such as Island, Forest, or Gate) and all original abilities. Third, they gain the Mountain subtype and the inherent mana ability '{T}: Add {R}.' This process happens in Layer 4 (type-changing effects) before Layer 6 (ability removal), meaning even if another effect tries to remove the Magus's abilities, the lands remain Mountains.

Common Mistakes

A frequent error is assuming that lands entering the battlefield after Magus of the Moon can still use their 'enters the battlefield' abilities. In reality, a land like a shockland or a fetchland will lose its triggered or static abilities before they can even apply. Another mistake is thinking the land's name changes; a land named 'Steam Vents' is still named 'Steam Vents,' but it is functionally a Mountain that taps for red.

When to Play It

Magus of the Moon is most effective against decks that rely on greedy mana bases or specific utility lands to function. By deploying it early, you can lock an opponent out of their required colors or prevent them from activating powerful effects. However, remember that it affects your nonbasic lands too, so ensure your deck is prepared to operate on predominantly red mana.

Interaction examples

Basic Land Synergy

Solemn Simulacrum

If you have Magus of the Moon on the battlefield, your nonbasic lands are Mountains, but your basic lands are untouched. When you play Solemn Simulacrum, its ability allows you to search for a 'basic land card.' This is a great way to ensure you have the specific colors you need (like Blue or Green) while your opponent is stuck with only Red mana from their nonbasic lands.

Tribal Double Triggers

Roaming Throne

If you cast Roaming Throne and choose 'Human' or 'Wizard' while Magus of the Moon is out, the Throne will not affect the Magus because Magus of the Moon has a continuous static ability, not a triggered ability. Static abilities do not 'trigger,' so Roaming Throne's double-trigger effect will not interact with the land-changing effect of the Magus.

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

How it works : Magus of the Moon

Original English text — Wizards of the Coast / Scryfall

#1March 19, 2021· Wizards of the Coast
If a nonbasic land has an ability that triggers "when" it enters the battlefield, it will lose that ability before it can trigger.
No other card is named in this ruling.
#2March 19, 2021· Wizards of the Coast
If a nonbasic land has an ability that causes it to enter the battlefield tapped, it will lose that ability before it can apply. The same is also true of any other abilities that modify how a land enters the battlefield or apply "as" a land enters the battlefield, such as that of Vesuva or Cavern of Souls.
No other card is named in this ruling.
#3March 19, 2021· Wizards of the Coast
Nonbasic lands lose any other land types and abilities they had. They gain the land type Mountain and gain the ability ": Add ."
No other card is named in this ruling.
#4March 19, 2021· Wizards of the Coast
Magus of the Moon doesn't affect names or supertypes. It won't turn any land into a basic land or remove the legendary supertype from a legendary land, and the lands won't be named "Mountain."
No other card is named in this ruling.
#5March 19, 2021· Wizards of the Coast
If Magus of the Moon loses its abilities, it continues to turn nonbasic lands into Mountains. This is because effects that change subtypes are applied before considering effects that remove abilities, regardless of the order in which those effects started.
No other card is named in this ruling.