When a player uses Ride the Wind to move a unit into combat at a battlefield, is that unit considered an attacker or defender?

Ruling: Units that join an ongoing combat gain the attacker/defender designation based on their controller's role in that combat, which is determined by who initially applied the contested status to the battlefield.

Sequence:

• The attacking/defending player designation is set by whichever player initially applied the contested status to the battlefield
• Units gain their attacker/defender designation based on their controller's role
• Any unit that subsequently joins the combat (such as via Ride the Wind) gains the designation assigned to their controller for that combat

Nuances:

• Even if the battlefield is not controlled by either player, the attacker is still the player who applied the contested status to the battlefield