Can Unyielding Spirit block damage from effects like Yasuo's attack trigger or Snapvine where the damage depends on might rather than a fixed number written on the card?

Ruling: Unyielding Spirit can block damage from effects like Yasuo's attack trigger that deal damage based on might. However, Challenge and Snapvine bypass Unyielding Spirit because the damage is dealt by units to each other rather than by the spell or ability itself.

Nuances:

• Fixed damage effects like Hidden Blade or effects that kill a unit directly do not work with Unyielding Spirit
• Challenge and Snapvine work the same way - they don't gain bonuses from effects like Void Gate and they bypass Unyielding Spirit
• The key distinction is whether it's the spell/ability dealing damage versus units dealing damage to each other; Unyielding Spirit only blocks damage from spells and abilities