If a 4 might unit with assault +1 attacks a battlefield and the opponent responds with Void Seeker, does the unit die or survive?

Ruling: The unit survives because assault applies when a unit becomes an attacker, which happens before the opponent can play actions like Void Seeker.

Sequence:

• Unit with assault +1 declares attack on battlefield
• Unit becomes an attacker and assault triggers, increasing might to 5
• Opponent gains priority to play actions
• If opponent plays Void Seeker at this point, the unit has 5 might and survives

Nuances:

• Assault only applies if there is an opposing unit at the battlefield; if attacking an open battlefield, assault would not be active