MTG Annihilator, Devoid and Eldrazi mechanics guide image showing massive Eldrazi creatures, colorless magic, sacrifice effects, ingest, emerge, and Commander battlefield chaos.

MTG Annihilator, Devoid & Eldrazi Mechanics Guide

Some Magic: The Gathering mechanics make a creature bigger. The Eldrazi mechanics make a creature feel like an eldritch horror devouring your world one permanent at a time — and they come with rules details that decide games.

Annihilator is the headline: an ability so punishing that opponents can lose a huge part of their board before blockers are even declared. But the Eldrazi bring a whole family of mechanics with them — devoid, ingest, processors, emerge — and each has a wrinkle that players consistently get wrong. Devoid in particular causes more Commander deckbuilding mistakes than almost any other keyword.

This guide covers all of them, with resolved examples and the exact rules behind each.

This is the first article in our series on advanced MTG mechanics, following our complete keyword abilities series. You can find the rest at the end of this article.

What Is Annihilator in MTG?

Annihilator (CR 702.86) is a triggered ability written as Annihilator N. It means: whenever this creature attacks, the defending player sacrifices N permanents.

Four details make it far more brutal than that sentence suggests:

  • It triggers on attack, not on damage. The creature does not need to connect. It does not even need to survive combat. The moment it is declared as an attacker, the trigger goes on the stack.
  • It resolves before blockers are declared. This is the crucial timing detail. Annihilator triggers and resolves during the declare attackers step, so the defending player sacrifices before they get to block — and anything they sacrifice is no longer available to block with.
  • The defending player chooses, and it can be anything. Any permanent counts: creatures, lands, artifacts, enchantments, tokens, even the planeswalker being attacked. Most players sacrifice tokens and spare lands, but against a high annihilator number there is nothing spare left.
  • It doesn't target. Hexproof, ward, and protection do nothing against it, because the ability never targets anything. We cover why that matters in our hexproof, ward and shroud guide.

Resolved Example — Killing the Attacker Doesn't Save You

Your opponent attacks with a creature that has annihilator 4. In response to the trigger, you cast removal and destroy the attacker. Do you still sacrifice?

Yes. The annihilator trigger is an independent object on the stack once it has triggered. Destroying, exiling, or bouncing the creature afterwards does nothing to the trigger — it still resolves and you still sacrifice four permanents. To avoid annihilator entirely you have to answer the creature before it is declared as an attacker.

Resolved Example — The Chump Block Trap

You control four creatures and face an attacker with annihilator 2. You plan to sacrifice two lands and chump block with a creature.

That works — but note the order. The sacrifice happens first, during declare attackers, and only afterwards do you declare blockers. If instead you sacrifice two creatures, those creatures are gone before you get to block with them. Against annihilator, deciding what to sacrifice is your blocking decision.

The Annihilator Cards Worth Knowing

Annihilator appears on a small, terrifying set of Eldrazi. The classics are Ulamog, the Infinite Gyre and Kozilek, Butcher of Truth, both carrying annihilator 4 — a number that ends most Commander games in two attacks.

It That Betrays is the cruellest design of the group: annihilator 2, plus an ability that returns the permanents your opponents sacrifice to the battlefield under your control. Every sacrifice becomes your gain, which turns a defensive decision into an impossible one.

The modern take is Ulamog, the Defiler, which has annihilator X, where X is the number of +1/+1 counters on it — a number based on the greatest mana value among cards in exile when it enters, which can climb higher than any fixed annihilator ever printed. It also carries a ward cost that demands sacrificing permanents just to target it.

What Is Devoid — and Why It Trips Up Commander Players

Devoid (CR 702.114) is a characteristic-defining ability with a deceptively simple meaning: the card is colorless.

The point of devoid was a design problem. The Eldrazi are colorless creatures, but Wizards wanted to print them with coloured mana costs so they would fit into specific colours' decks. Devoid was the answer: the card costs coloured mana to cast, but it is colorless for every purpose in the game.

Two properties matter:

  • It functions everywhere. Unlike most abilities, devoid works in every zone — hand, graveyard, library, exile, the stack, even outside the game. A devoid card is colorless at all times.
  • It does NOT change colour identity. This is the trap.

The Colour Identity Trap

Here is the mistake that ruins Commander decklists: devoid makes a card colorless, but colour identity still counts the coloured mana symbols printed on the card — and those coloured symbols are still there in the mana cost.

So a devoid creature that costs black mana is a colorless card, but its colour identity is black. It cannot go in a deck whose commander has no black in its colour identity, even though the card itself is colorless. Players see "this card has no color" and assume it goes in any deck. It does not.

If you are building around colorless payoffs, the cards you actually want are naturally colorless ones — Eldrazi with genuinely colorless mana costs — not devoid cards with coloured costs.

Ingest and Processors

Ingest (CR 702.115) is a triggered ability: whenever a creature with ingest deals combat damage to a player, that player exiles the top card of their library.

Two notes. First, it is one card per instance of combat damage, regardless of the creature's power — a 1/1 with ingest exiles exactly as much as a 5/5 with ingest. Second, if the player's library is empty, nothing happens; they do not lose the game from it (that only comes from actually attempting to draw from an empty library).

On its own, ingest does very little. Its purpose is fuel. Processor is not a keyword ability but an Eldrazi creature type, and Processors have abilities that consume cards exiled from opponents — the cards ingest put there. The two mechanics were designed as a pair: ingest fills the exile zone, Processors eat it.

It is a flavour-perfect combination and a mechanically fragile one, which is likely why ingest has rarely been revisited as a major mechanic. But if you are building an Eldrazi deck around the Battle for Zendikar era, understanding that ingest is a setup mechanic rather than a standalone threat is the key to using it.

Emerge

Emerge is an alternative cost that lets an Eldrazi claw its way onto the battlefield by consuming one of your own creatures. To cast a spell for its emerge cost, you sacrifice a creature, and the generic portion of the emerge cost is reduced by that sacrificed creature's mana value. The coloured mana in the emerge cost still has to be paid.

The practical effect is that a large Eldrazi becomes dramatically cheaper if you have a sizeable creature to feed it — and it pairs beautifully with creatures whose value comes from entering or dying, since you get that value and then convert the body into a much bigger threat.

Because emerge is an alternative cost, it changes what you pay — not what the card is. The spell's mana value on the stack is still based on its printed mana cost, not on the amount of mana you actually spent. Also, emerge does not change timing: unless the card has flash or another effect says otherwise, you still cast it only when you could normally cast that creature spell.

Quick Reference: Eldrazi Mechanics

Question Answer
When does annihilator trigger? When the creature is declared as an attacker
Does annihilator resolve before blockers? Yes — sacrificed creatures can't block
Does killing the attacker stop annihilator? No — the trigger resolves independently
Does hexproof or protection stop annihilator? No — it doesn't target
Who chooses the sacrificed permanents? The defending player, and any permanent type counts
Does devoid make a card colorless? Yes, in every zone, even outside the game
Does devoid change colour identity? No — coloured mana symbols still count for Commander
How much does ingest exile? One card per instance of combat damage, regardless of power
What does emerge do? Alternative cost: sacrifice a creature to reduce the generic cost
Do multiple instances of annihilator stack? Yes — each triggers separately

Eldrazi in Commander

Commander is where the Eldrazi belong. Games go long, mana climbs high, and a single enormous colorless threat can dominate a table — which is exactly what these creatures were designed to do.

Annihilator is disproportionately strong in multiplayer. In a duel, annihilator 4 is devastating. In a four-player game, you attack a different opponent each turn and dismantle three boards in a rotation. Few effects punish a developed board this hard, and none of the usual protection tools stop it.

The colorless payoff shell is real. Lands like Eldrazi Temple and Eye of Ugin exist specifically to accelerate and find Eldrazi, turning a "cast a ten-mana creature" plan into something achievable several turns earlier.

Not every big Eldrazi has annihilator, and building well means knowing which does what. Ulamog, the Ceaseless Hunger, Kozilek, the Great Distortion, and Emrakul, the Promised End are all format-warping threats that win through their cast triggers and abilities rather than through annihilator. The Modern Horizons 3 titans — Kozilek, the Broken Reality and Emrakul, the World Anew — are built as commanders for colorless strategies.

And for a genuinely absurd payoff, Zhulodok, Void Gorger gives colorless spells you cast from your hand with mana value 7 or greater "cascade, cascade" — two separate cascade triggers from a single spell — a mechanic we cover in detail in our cascade, storm and suspend guide. Casting one huge Eldrazi and getting two free spells off the top is exactly the kind of thing that ends a Commander game.

Void Winnower deserves a mention as the purest expression of Eldrazi oppression: it does not attack anyone into submission, it simply switches off half of every opponent's deck.

You can find these threats and the colorless shell that supports them in our full catalogue, or import your decklist directly with our decklist search tool.

Frequently Asked Questions

Can I respond to annihilator by killing the attacking creature?

You can kill it, but you will still sacrifice. Once annihilator has triggered, the ability exists independently on the stack — removing the creature does not remove the trigger. The only way to avoid annihilator is to deal with the creature before attackers are declared, or to have an effect that prevents you from sacrificing.

Do I sacrifice before or after I declare blockers?

Before. Annihilator triggers and resolves during the declare attackers step, which comes before the declare blockers step. Anything you sacrifice is gone before blocks happen, so sacrificing your best blocker is usually a mistake.

Can I sacrifice tapped permanents to annihilator?

Yes. The ability just says sacrifice N permanents — tapped or untapped makes no difference, and you choose which ones. Sacrificing tapped lands and spare tokens while keeping untapped blockers available is the standard way to minimise the damage.

Does annihilator work when the creature attacks a planeswalker?

Yes. The defending player in that case is the planeswalker's controller, and they sacrifice as normal. They may even choose to sacrifice the planeswalker being attacked — in which case the creature remains attacking, can still be blocked, and simply deals no damage if it goes unblocked.

Can I put a devoid card in any Commander deck because it's colorless?

No, and this is the most common devoid mistake. Devoid makes the card colorless, but colour identity for Commander deckbuilding is determined by the mana symbols on the card. A devoid card with red mana in its cost has a red colour identity and can only go in decks whose commander includes red. Colorless and colour identity are two different things.

Does ingest exile more cards if the creature has higher power?

No. Ingest exiles exactly one card each time the creature deals combat damage to a player, regardless of how much damage was dealt. A 1/1 with ingest and a 6/6 with ingest exile the same single card.

Is emerge a cost reduction or an alternative cost?

An alternative cost. You are not reducing the spell's normal mana cost — you are paying a different cost entirely, which involves sacrificing a creature and paying the emerge cost with its generic portion reduced by the sacrificed creature's mana value. The card's mana value itself does not change based on what you paid.

More guides in our advanced mechanics series:

The keyword abilities series:

Related guides:

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