If G Yasuo attacks and triggers his ability to strike a unit, but is killed or removed by Hidden Blade in response, does his damage ability still resolve and kill the targeted unit?

Ruling: No, Yasuo's ability will not deal damage if he is killed or removed before it resolves. The ability fizzles because it deals damage to a unit "here" (at Yasuo's location), and if Yasuo is no longer on the battlefield, the effect cannot resolve.

Sequence:

• Yasuo attacks and his ability triggers, targeting an opponent's unit
• In response, Hidden Blade kills or removes Yasuo
• Yasuo's ability attempts to resolve but fails because Yasuo is no longer "here"
• The targeted unit takes no damage

Nuances:

• This ruling applies to any ability that references "here" - the source must still exist at that location for the effect to resolve
• If Yasuo is moved to a different location (like being sent back to base with Zhonya), the same principle applies - the ability trigger still exists on the chain but cannot resolve because the targeted unit is no longer at the same location as Yasuo
• Effects that specify a fixed amount of damage (like "deal 5 damage") would still resolve even if the source dies
• Under current rules, if a unit dies, it is treated as having 0 Might, though this may change in future rules updates