What happens if you kill a unit with an attack trigger before it resolves like Azir?

If you kill a unit with an "attack trigger" (or any triggered ability) after it has been added to the chain, the ability still resolves, but it may fail to have an effect depending on its specific text.

According to RiftJudge FAQ #6035 and Rule 356.3.e.6, triggered abilities resolve as much as they can, even if the source unit is no longer on the board. However, if the ability requires valid targets or references the unit's location (e.g., "here"), those parts will fail if the unit is no longer at the specified location or no longer exists.

Key Mechanics:

1. No "Fizzling": In Riftbound, there is no "fizzling" in the traditional sense. The ability always resolves; it just potentially does nothing if its conditions cannot be met.
2. Location References: If an ability references "here" or "this battlefield," and the unit is killed or moved, the game can no longer identify the location, causing that part of the effect to fail (FAQ #2127, FAQ #2443).
3. Stat References: If an ability references the unit's stats (like "my might"), and the unit is killed, the game treats those stats as "null," causing calculations based on them to be ignored (Rule 356.3.e.12).
4. Independent Effects: If an ability has a simple effect that does not depend on the unit's location or stats (e.g., "draw 1 card"), that part of the ability will still resolve successfully even if the unit is dead (FAQ #6035).

Example Sequence (Killing a unit with an attack trigger):

1. Trigger: The unit attacks, and its "When I attack" ability is added to the chain.
2. Reaction: You play a card to kill the unit. The unit is moved to the trash.
3. Resolution: The chain resolves. The game checks the ability's instructions:
   • If the ability says "Deal X damage to a unit," it resolves normally (assuming the target is still valid).
   • If the ability says "Deal X damage to a unit here," it fails because the source unit is no longer "here" to define the location.
   • If the ability says "Deal damage equal to my might," it fails because the unit's might is now "null."

Summary: The ability will always attempt to resolve, but if it relies on the unit's presence, location, or stats, it will likely do nothing.