Magus of the Coffers 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

, : Add for each Swamp you control.

Complete guide

Magus of the Coffers is a powerful mana engine that mirrors the effect of the iconic Cabal Coffers. As a creature-based version of the land, it allows Mono-Black players to generate massive amounts of mana to fuel their most expensive spells. Understanding how to maximize your Swamp count is the key to mastering this Human Wizard.

Harnessing the Swamps

Magus of the Coffers has an activated ability that costs two generic mana and requires you to tap it. Upon resolution, it checks the number of lands you control with the 'Swamp' subtype. You then add that much Black mana to your mana pool. This includes Basic Swamps and any non-basic lands that specifically have the Swamp type listed on their type line.

Step-by-Step Resolution

First, ensure Magus of the Coffers does not have summoning sickness, as the ability requires tapping. Pay two generic mana and tap the creature to put the ability on the stack. When the ability resolves, count every land you control that is a Swamp. For each one counted, you add one Black mana ({B}). This happens all at once during resolution, not as multiple separate triggers.

Common Pitfalls

A frequent mistake is forgetting that Magus of the Coffers counts the subtype, not the name. While a Basic Swamp counts, a land like Reliquary Tower does not because it lacks the 'Swamp' type. Additionally, remember that the Magus's ability is an activated mana ability; it does not use the stack in a way that can be responded to once the cost is paid, and it cannot be targeted by spells like Stifle.

Strategic Timing

Because this ability requires you to pay two mana to activate, it only starts providing a profit once you control three or more Swamps. It is often best to activate this during your main phase to cast large creatures or sorceries, or during an opponent's turn if you need to hold up mana for instant-speed interaction.

Interaction examples

Boosting the Count

Solemn Simulacrum

You control Magus of the Coffers and three Swamps. You cast Solemn Simulacrum, using its enters-the-battlefield ability to search your library for a basic Swamp and put it onto the battlefield. Now, when you activate Magus of the Coffers, you will count four Swamps, producing four Black mana for a net gain of two mana.

Creature Type Synergy

Roaming Throne

You have Magus of the Coffers and Roaming Throne on the battlefield, with Roaming Throne having chosen 'Human' or 'Wizard'. Note that Magus of the Coffers has an activated ability, not a triggered ability. Therefore, Roaming Throne's effect will not cause the Magus's mana-generating ability to trigger an additional time, as activated abilities (indicated by a colon) are not affected by Roaming Throne.

Solo Efficiency

If you control Magus of the Coffers and six Swamps, you pay two mana and tap the Magus. The ability resolves, sees six Swamps, and adds six Black mana to your pool. After accounting for the activation cost, you have gained four additional Black mana to spend during that phase.

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