How do focus and priority work in Riftbound, particularly during showdowns?

Ruling: Focus is a showdown-specific mechanic that determines who can play action-speed spells. The player with focus can play action or reaction spells to start a chain, while the player without focus can only play reaction spells in response to an existing chain.

Sequence:

• When a showdown begins, the attacker has focus and priority
• Any "when I attack" or "when I defend" triggers create an initial chain that can only be responded to with reactions
• After that chain resolves, the attacker (with focus) can start a new chain with an action or reaction spell
• Once that chain resolves, focus passes to the defender
• The defender can now start a chain with an action or reaction spell
• After their chain resolves, focus passes back to the attacker
• This continues until both players consecutively pass with an empty chain
• When both players pass with no chain, the showdown proceeds to combat damage

Nuances:

• If you pass priority while a chain is open, you retain focus but pass priority only
• If you pass with an empty chain (no active chain), you pass both focus and priority to your opponent
• Focus only exists during showdowns; outside of showdowns, you cannot play action spells on your opponent's turn
• Units and gear create chains when played, but they immediately resolve and cannot be responded to (unless they have "when played" triggers)
• Even if units leave the battlefield during a showdown, players can continue starting chains until both pass