When do Deathknell abilities resolve during combat?

Ruling: Deathknell abilities resolve at the end of the combat special cleanup, which occurs after units are healed and after attackers have been recalled (if defenders are still present).

Sequence:

1. Combat damage is dealt
2. Units with lethal damage trigger their Deathknell abilities (added as pending items to the chain)
3. Units with lethal damage are moved to the trash
4. All surviving units on the battlefield are healed
5. Attackers are recalled if defenders are still present
6. Combat cleanup ends
7. Deathknell triggers resolve

Nuances:

• Because healing occurs before Deathknell abilities resolve, you cannot use Deathknell effects to finish off enemy units that survived combat damage, as they will be healed to full health first.
• Deathknell effects resolve before a player establishes control of the battlefield and potentially conquers it.