Can a player use Arcane Shift to replay a unit to a battlefield they are attacking (but don't control) after the unit was removed by Void Seeker?
Ruling: No, the attacking player cannot replay the unit to that battlefield because they do not control it. Arcane Shift requires the player to control the battlefield where they want to replay the unit.
Nuances:
- The attacker does not control the battlefield they are attacking
- This restriction only applies when the Arcane player is the attacker; if they controlled the battlefield, they could replay the unit there