Does Champion Voli's 5 damage resolve before the opponent can play Rebuke during a showdown?

Ruling: Yes, the 5 damage resolves before Rebuke can be played. Rebuke cannot be used as a response to Voli - Furious' ability.

Sequence:

• Voli's 'on attack' ability is added to the initial chain of the showdown
• Either player can play reactions on this chain
• The initial chain finishes resolving (including the 5 damage)
• Actions (like Rebuke) can only be played during open states after the initial chain has finished resolving

Nuances:

• Actions can only be played on open states during showdowns, not as responses to abilities on the initial chain
• Reactions can be played on the initial chain, but Rebuke is an action, not a reaction