Does Deathnell trigger in the discard pile or on the field?

According to the official rules and FAQs for Riftbound, the Deathknell trigger is placed on the chain as a "Pending Item" at the moment a unit is killed.

Here is the mechanical breakdown of how Deathknell functions:

1. Triggering: When the event that kills a permanent with Deathknell occurs, the ability triggers. Because the trigger is placed on the chain before the unit is moved to the trash (Rule 808.1.d.2), the information about the unit is captured at the moment of death (Rule 808.1.d.3).
2. Creation: According to RiftJudge FAQ #5439, the trigger is created from the trash. This refers to the fact that the ability is processed after the unit has reached the trash zone, and the owner's trash serves as the reference point for the card's existence.
3. Resolution: Once added to the chain, the Deathknell ability functions like any other triggered ability. It resolves during the chain's execution, regardless of whether the unit has ceased to exist (in the case of tokens) or has moved to the trash pile.

Summary: Deathknell is triggered by the act of dying while the unit is on the battlefield, and its origin is considered to be the trash zone once the card has been moved there.

Note: I could not fully verify this ruling against the retrieved rules.