Chainer's Torment — ruling 1

If another effect causes the Nightmare Horror token's power or toughness to be a number other than X immediately after it enters the battlefield, the amount of damage it deals to you is still X, not its modified power or toughness.

Chainer's Torment — ruling 2

If an effect such as that of Anointed Procession causes the final chapter ability of Chainer's Torment to create two Nightmare Horror tokens, each will deal X damage to you.

Chainer's Torment — ruling 3

In a Two-Headed Giant game, the first chapter abilities of Chainer's Torment each cause the opposing team to lose 4 life and you to gain 2 life.

Chainer's Torment — ruling 4

As a Saga enters the battlefield, its controller puts a lore counter on it. As your precombat main phase begins (immediately after your draw step), you put another lore counter on each Saga you control. Putting a lore counter on a Saga in either of these ways doesn't use the stack.

Chainer's Torment — ruling 5

Each symbol on the left of a Saga's text box represents a chapter ability. A chapter ability is a triggered ability that triggers when a lore counter that is put on the Saga causes the number of lore counters on the Saga to become equal to or greater than the ability's chapter number. Chapter abilities are put onto the stack and may be responded to.

Chainer's Torment — ruling 6

A chapter ability doesn't trigger if a lore counter is put on a Saga that already had a number of lore counters greater than or equal to that chapter's number. For example, the third lore counter put on a Saga causes the III chapter ability to trigger, but I and II won't trigger again.

Chainer's Torment — ruling 7

Once a chapter ability has triggered, the ability on the stack won't be affected if the Saga gains or loses counters, or if it leaves the battlefield.

Chainer's Torment — ruling 8

If multiple chapter abilities trigger at the same time, their controller puts them on the stack in any order. If any of them require targets, those targets are chosen as you put the abilities on the stack, before any of those abilities resolve.

Chainer's Torment : règles, fonctionnement et interactions (MTG)

Chainer's Torment 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

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I, II — This Saga deals 2 damage to each opponent and you gain 2 life. III — Create an X/X black Nightmare Horror creature token, where X is half your life total, rounded up. It deals X damage to you.

How it works : Chainer's Torment

Original English text — Wizards of the Coast / Scryfall

#1April 27, 2018· Wizards of the Coast
If another effect causes the Nightmare Horror token's power or toughness to be a number other than X immediately after it enters the battlefield, the amount of damage it deals to you is still X, not its modified power or toughness.
Card named in this ruling
Nightmare Horror
#2April 27, 2018· Wizards of the Coast
If an effect such as that of Anointed Procession causes the final chapter ability of Chainer's Torment to create two Nightmare Horror tokens, each will deal X damage to you.
Card named in this ruling
Nightmare Horror
#3April 27, 2018· Wizards of the Coast
In a Two-Headed Giant game, the first chapter abilities of Chainer's Torment each cause the opposing team to lose 4 life and you to gain 2 life.
No other card is named in this ruling.
#4April 27, 2018· Wizards of the Coast
As a Saga enters the battlefield, its controller puts a lore counter on it. As your precombat main phase begins (immediately after your draw step), you put another lore counter on each Saga you control. Putting a lore counter on a Saga in either of these ways doesn't use the stack.
No other card is named in this ruling.
#5April 27, 2018· Wizards of the Coast
Each symbol on the left of a Saga's text box represents a chapter ability. A chapter ability is a triggered ability that triggers when a lore counter that is put on the Saga causes the number of lore counters on the Saga to become equal to or greater than the ability's chapter number. Chapter abilities are put onto the stack and may be responded to.
No other card is named in this ruling.
#6April 27, 2018· Wizards of the Coast
A chapter ability doesn't trigger if a lore counter is put on a Saga that already had a number of lore counters greater than or equal to that chapter's number. For example, the third lore counter put on a Saga causes the III chapter ability to trigger, but I and II won't trigger again.
No other card is named in this ruling.
#7April 27, 2018· Wizards of the Coast
Once a chapter ability has triggered, the ability on the stack won't be affected if the Saga gains or loses counters, or if it leaves the battlefield.
No other card is named in this ruling.
#8April 27, 2018· Wizards of the Coast
If multiple chapter abilities trigger at the same time, their controller puts them on the stack in any order. If any of them require targets, those targets are chosen as you put the abilities on the stack, before any of those abilities resolve.
No other card is named in this ruling.
#9April 27, 2018· Wizards of the Coast
If counters are removed from a Saga, the appropriate chapter abilities will trigger again when the Saga receives lore counters. Removing lore counters won't cause a previous chapter ability to trigger.
No other card is named in this ruling.
#10April 27, 2018· Wizards of the Coast
Once the number of lore counters on a Saga is greater than or equal to the greatest number among its chapter abilities—in the Dominaria set, this is always three—the Saga's controller sacrifices it as soon as its chapter ability has left the stack, most likely by resolving or being countered. This state-based action doesn't use the stack.
No other card is named in this ruling.