Narset, Enlightened Exile — ruling 1

Narset's first ability gives it prowess while it's on the battlefield.

Narset, Enlightened Exile — ruling 2

Once a prowess ability triggers, causing the creature to lose prowess by removing Narset, Enlightened Exile won't affect that ability. The creature will still get +1/+1 until end of turn.

Narset, Enlightened Exile — ruling 3

If a creature has multiple instances of prowess, each triggers separately.

Narset, Enlightened Exile — ruling 4

You cast the copy while the ability is resolving and still on the stack. You can't wait to cast it later in the turn.

Narset, Enlightened Exile — ruling 5

If you cast a spell "without paying its mana cost," you can't pay any alternative costs. You can, however, pay additional costs, such as kicker costs. If the card has any mandatory additional costs, you must pay those.

Narset, Enlightened Exile — ruling 6

If the spell you cast has {X} in its mana cost, you must choose 0 as the value of X.

Narset, Enlightened Exile — ruling 7

If you don't want to cast the copy, you can choose not to; the copy ceases to exist the next time state-based actions are performed.

Narset, Enlightened Exile — ruling 8

If another effect causes Narset's power to be less than or equal to the mana value of the target card as the ability tries to resolve, the target is illegal. The card won't be exiled, and you won't get to cast a copy.

Narset, Enlightened Exile : règles, fonctionnement et interactions (MTG)

Narset, Enlightened Exile 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

Creatures you control have prowess. Whenever Narset attacks, exile target noncreature, nonland card with mana value less than Narset's power from a graveyard and copy it. You may cast the copy without paying its mana cost.

How it works : Narset, Enlightened Exile

Original English text — Wizards of the Coast / Scryfall

#1May 12, 2023· Wizards of the Coast
Narset's first ability gives it prowess while it's on the battlefield.
No other card is named in this ruling.
#2May 12, 2023· Wizards of the Coast
Once a prowess ability triggers, causing the creature to lose prowess by removing Narset, Enlightened Exile won't affect that ability. The creature will still get +1/+1 until end of turn.
No other card is named in this ruling.
#3May 12, 2023· Wizards of the Coast
If a creature has multiple instances of prowess, each triggers separately.
No other card is named in this ruling.
#4May 12, 2023· Wizards of the Coast
You cast the copy while the ability is resolving and still on the stack. You can't wait to cast it later in the turn.
No other card is named in this ruling.
#5May 12, 2023· Wizards of the Coast
If you cast a spell "without paying its mana cost," you can't pay any alternative costs. You can, however, pay additional costs, such as kicker costs. If the card has any mandatory additional costs, you must pay those.
No other card is named in this ruling.
#6May 12, 2023· Wizards of the Coast
If the spell you cast has in its mana cost, you must choose 0 as the value of X.
No other card is named in this ruling.
#7May 12, 2023· Wizards of the Coast
If you don't want to cast the copy, you can choose not to; the copy ceases to exist the next time state-based actions are performed.
No other card is named in this ruling.
#8May 12, 2023· Wizards of the Coast
If another effect causes Narset's power to be less than or equal to the mana value of the target card as the ability tries to resolve, the target is illegal. The card won't be exiled, and you won't get to cast a copy.
No other card is named in this ruling.