If an opponent uses Falling Star on a unit that has been shrunk to 2 health, hitting it twice, and Sett the Boss is used to heal the unit, does the unit still take the remaining 3 damage from Falling Star and die, or does Falling Star fully resolve before replacement effects happen?

Ruling: The unit still takes the remaining 3 damage from Falling Star after its death is replaced by Sett the Boss's healing effect, because it remains a legal target for the remaining Falling Star triggers.

Sequence:

• Falling Star begins dealing damage to the unit
• When the unit would die from damage, Sett the Boss's replacement effect intercedes immediately
• The unit is healed instead of dying
• Falling Star continues to deal its remaining damage to the unit (still a legal target)

Nuances:

• Sett the Boss is a replacement effect that intercedes as soon as its condition is fulfilled; it doesn't wait for other effects to resolve
• Sett the Boss has been errata'd to heal from all damage, not just combat damage