Does a 5 might unit die if it takes 4 damage from Void Seeker and then is reduced by 1 might from Stupefy?

Ruling: Yes, the unit dies. After Stupefy resolves, there is a cleanup step where the unit is at 4 might with 4 damage marked on it, which triggers lethal damage removal.

Sequence:

• Void Seeker deals 4 damage to the 5 might unit (unit is now 5 might with 4 damage)
• Stupefy reduces might by 1 (unit is now 4 might with 4 damage)
• Cleanup step occurs, removing units with damage equal to or greater than their might
• Unit dies because 4 damage equals 4 might

Nuances:

• There is no separate HP stat in Riftbound, only Might
• The order of playing Void Seeker and Stupefy doesn't matter for this outcome
• Stupefy cannot kill a unit on its own (reduces might to minimum of 1)
• Cleanup steps occur after conquering a battlefield or at end of turn