If a 7 Might unit has 6 damage marked on it, then Stupefy reduces its Might to 6, does the unit die and what counts as killing it?

Ruling: The unit dies after Stupefy resolves during the next Cleanup, because it has damage marked on it equal to its Might. However, Stupefy is not considered the spell that killed the unit because it did not apply damage.

Sequence:

• Falling Comet deals 6 damage to the 7 Might unit
• Stupefy resolves, reducing the unit's Might to 6
• During Cleanup, the unit is killed because it has 6 damage marked on it equaling its 6 Might
• Falling Comet (the spell that applied damage immediately prior to that Cleanup) is responsible for the kill action, not Stupefy

Nuances:

• Only spells or abilities that applied damage can be responsible for kill actions during Cleanup, not effects that reduce Might