Ob Nixilis, Unshackled — ruling 1

Ob Nixilis's first triggered ability won't trigger if you search an opponent's library or if an opponent searches another player's library.

Ob Nixilis, Unshackled — ruling 2

If the opponent controls no creatures when the first triggered ability resolves, that player still loses 10 life.

Ob Nixilis, Unshackled — ruling 3

The first triggered ability won't be put on the stack until after the spell or ability causing the opponent to search their library finishes resolving. Notably, if that spell or ability causes any other abilities to trigger (for example, if the opponent searched for a creature card and put it onto the battlefield), those abilities and Ob Nixilis's triggered ability will go on the stack together. The active player puts all of their abilities on the stack in any order, then each other player in turn order does the same. The last ability put onto the stack this way will be the first to resolve, and so on.

Ob Nixilis, Unshackled : règles, fonctionnement et interactions (MTG)

Ob Nixilis, Unshackled 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

Flying, trample Whenever an opponent searches their library, that player sacrifices a creature of their choice and loses 10 life. Whenever another creature dies, put a +1/+1 counter on Ob Nixilis.

Complete guide

Ob Nixilis, Unshackled is a powerhouse Demon that punishes opponents for looking through their decks and grows stronger with every casualty on the field. This legendary creature is a formidable win condition that combines high-flying aggression with a punishing tax on standard game actions.

Punishing the Search

The most feared ability of Ob Nixilis, Unshackled is its search-hate trigger. Whenever an opponent searches their library, they must sacrifice a creature and lose 10 life. This effect doesn't prevent the search, but it makes the cost of doing so extremely high. It is important to note that this only triggers if an opponent searches their own library; if you search their library or they search yours, the ability does not fire.

How it Resolves

The ability that punishes searching is a triggered ability. It won't be put on the stack until the spell or ability causing the search has completely finished resolving. If multiple things happen at once—for example, a search that puts a creature into play—the search-punish trigger and any enter-the-battlefield triggers are put on the stack in APNAP (Active Player, Next Active Player) order. The player whose turn it is puts their triggers on first, followed by others in turn order. The last ability put on the stack resolves first.

Feeding the Demon

Ob Nixilis also grows whenever another creature dies. This includes your own creatures and your opponents' creatures. This creates a terrifying synergy with his search-hate: when an opponent searches their library, they are forced to sacrifice a creature, which in turn grants Ob Nixilis a +1/+1 counter. This ensures that even if you aren't attacking, the Demon is constantly scaling in power.

Common Mistakes

A common misconception is that the life loss is dependent on the sacrifice. If an opponent searches their library but controls no creatures to sacrifice, they still lose the 10 life. Additionally, remember that Ob Nixilis's growth ability triggers whenever 'another creature' dies; it does not count itself if it is destroyed at the same time as other creatures unless otherwise specified by state-based actions.

Interaction examples

The Price of a Search

If an opponent plays a spell to search for a land, they complete the search and put the land into play. Immediately after that spell finishes, Ob Nixilis's trigger is put on the stack. When it resolves, that opponent must choose a creature they control to sacrifice and their life total is reduced by 10. Ob Nixilis then receives a +1/+1 counter because a creature died.

Synergistic Devotion

Gray Merchant of Asphodel

With Ob Nixilis on the battlefield, your devotion to black is increased by two. When you play Gray Merchant of Asphodel, Ob Nixilis contributes to the total life drained from your opponents. If Gray Merchant's entry triggered another effect that caused an opponent to search, Ob Nixilis would potentially kill off a creature to grow even larger.

The Death Toll

Syr Konrad, the Grim

When an opponent searches their library and Ob Nixilis forces them to sacrifice a creature, two things happen: Ob Nixilis gets a +1/+1 counter, and Syr Konrad, the Grim triggers to deal 1 damage to each opponent. Together, these cards make the act of a creature dying twice as painful for your enemies.

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

How it works : Ob Nixilis, Unshackled

Original English text — Wizards of the Coast / Scryfall

#1July 18, 2014· Wizards of the Coast
Ob Nixilis's first triggered ability won't trigger if you search an opponent's library or if an opponent searches another player's library.
No other card is named in this ruling.
#2July 18, 2014· Wizards of the Coast
If the opponent controls no creatures when the first triggered ability resolves, that player still loses 10 life.
No other card is named in this ruling.
#3July 18, 2014· Wizards of the Coast
The first triggered ability won't be put on the stack until after the spell or ability causing the opponent to search their library finishes resolving. Notably, if that spell or ability causes any other abilities to trigger (for example, if the opponent searched for a creature card and put it onto the battlefield), those abilities and Ob Nixilis's triggered ability will go on the stack together. The active player puts all of their abilities on the stack in any order, then each other player in turn order does the same. The last ability put onto the stack this way will be the first to resolve, and so on.
No other card is named in this ruling.