If defending and playing Shen as a reaction during defender focus, does Shen join the showdown and combat? If playing Ride the Wind onto a battlefield with an active showdown, does that unit join the showdown/battle or queue up a new showdown?

Ruling: A unit moved into an ongoing combat that its controller is part of will join the combat and gain the appropriate designation (attacker or defender). A unit moved into an ongoing showdown that its controller is part of will join that showdown. If moved to a showdown their controller is not part of, a combat will be staged there and begin after the current showdown ends.

Sequence:

• If you move a unit to a showdown you're already part of, it joins immediately
• If you move a unit to a showdown you're not part of, the combat is staged
• When all players pass focus instead of starting a chain in succession, the current showdown ends
• The staged combat then begins, with whoever first applied contested to the battlefield as the attacker

Nuances:

• You can only play Shen to locations you control (your base or any battlefields you control)
• As a defender, you generally control the battlefield, but not always (e.g., in surprise defense scenarios where the attacker attacks an open battlefield and you move a unit in)
• Shen gains the bonus Might from Shield when played during combat
• Control of a battlefield is retained throughout combat if you controlled it when combat started, until the end when it's resolving