When Yasuo (Champion) attacks a battlefield controlled by Ahri (Legend), whose 'when attacking/when attacked' ability triggers first on the chain?

Ruling: The attacker's triggers go on the chain first (on the bottom), followed by the defender's triggers. This means the defender's triggers resolve first, then the attacker's triggers resolve second.

Sequence:

• Attacker's "when I attack" triggers go on chain first (bottom of chain)
• Defender's "when enemy unit attacks" triggers go on chain second (top of chain)
• Chain resolves top to bottom, so defender's triggers resolve first
• Attacker's triggers resolve last

Nuances:

• In the Yasuo vs Ahri example: Ahri's -1 ability resolves first, reducing Yasuo to 5 might, then Yasuo's damage ability resolves dealing 5 damage (not 6)
• This ordering is based on attacker vs defender, not turn player vs non-turn player
• There was initial confusion about whether turn player or attacker determines priority, but the correct answer is that attacker's triggers go on chain first