Does Draven, Audacious need to remain at the battlefield to trigger his ability when you win combat?

Ruling: Yes, Draven must remain at the battlefield when combat concludes for his ability to trigger. If Draven is moved away during combat (even during Showdown), he loses his Attacker/Defender designation and is no longer participating in that combat, so his ability will not trigger even if you win.

Sequence:

• Draven enters a contested battlefield and gains Attacker/Defender designation (now in combat)
• If Draven is moved to base during Showdown, he loses his designation and is no longer in combat
• Combat continues and resolves
• If you win the combat (your units remain), Draven's ability does NOT trigger because he was not present
• For the ability to trigger: Draven must have Attacker/Defender designation when combat concludes

Nuances:

• You win a combat if only your units remain at the battlefield after combat concludes (determined at end of Resolution step)
• Being "in combat" requires having the Attacker or Defender designation
• Leaving the battlefield causes a unit to lose its Attacker/Defender designation
• If both players' units are removed during combat, neither player wins (it's a tie)
• Draven can trigger his ability without dealing damage (e.g., if opponent's units are removed via spells during Showdown)
• The "I" in "when I win a combat" refers to Draven as a unit-character, requiring him to be present/participating when combat is won