If a 5 Might unit has 4 damage marked on it from Void Seeker, then Stupefy reduces it to 4 Might (causing it to die), does Immortal Phoenix trigger to return from trash?

Ruling: Immortal Phoenix does NOT trigger. The spell that resolved immediately prior to the cleanup was Stupefy, which did not apply damage. Only spells that both apply damage AND resolve immediately prior to the cleanup get kill credit.

Nuances:

• Void Seeker cannot get kill credit because another spell (Stupefy) resolved between Void Seeker and the cleanup where the unit died
• "Resolved immediately prior" means with nothing in between, not "most recent spell that dealt damage"
• The unit dies from system rules checking Might vs marked damage during cleanup, not directly from either spell
• Strategic takeaway: Use Might reductions before damage spells when playing against Immortal Phoenix