If Yasuo Remorseful moves to a battlefield with an enemy unit and uses his attack trigger targeting that enemy unit, but the opponent responds with Hidden Blade to kill Yasuo, does the attack trigger still deal damage to the enemy unit?

Ruling: No, the attack trigger does not deal damage to the enemy unit. When the ability resolves and Yasuo is no longer on the battlefield, "here" cannot be evaluated, so the ability has no effect.

Sequence:

• Yasuo moves to a battlefield with an enemy unit
• Attack trigger goes on the stack targeting the enemy unit
• Opponent responds with Hidden Blade, killing Yasuo
• When the attack trigger resolves, "here" cannot be determined because Yasuo is dead
• The ability does not take effect

Nuances:

• Riftbound rechecks spells and abilities at resolution, so location-dependent effects like "here" must be valid when the ability resolves, not just when it triggers