If an attacker uses Retreat on their only unit, does combat end immediately or does focus continue to pass between players, allowing the defender to play actions?

Ruling: Focus continues to pass between players after Retreat resolves. The showdown remains active as long as the attacker moved to a battlefield to attempt to conquer it, even if they have no units present after Retreat.

Sequence:

• Retreat resolves, removing the attacker's only unit
• Priority/focus continues to pass between players
• Both players must pass without starting a chain
• Then the game proceeds to cleanup and combat showdown ends if no units from either side are present

Nuances:

• The defender can still play actions after Retreat resolves
• The showdown state persists as long as the attacker initially moved to a battlefield to attempt conquest, regardless of whether units remain