How does Unyielding Spirit work to prevent damage, and what types of damage/effects does it block or not block?

Ruling: Unyielding Spirit prevents damage from spells and abilities for the rest of the turn when played. It does not prevent effects that don't deal damage (like might reduction, banish effects, or units dealing damage to each other).

Sequence:

• Can be played as a reaction (chain 2) to prevent damage from a spell like Singularity
• Prevents the damage portion only; spells/abilities can still be played and resolve their non-damage effects
• Lasts for the remainder of the turn

Nuances:

• Blocks damage from spells (like Singularity) and unit abilities (like Tibbers, Anivia, Yasuo)
• Does NOT block damage from units fighting each other (Challenge, Gentlemen Duel)
• Does NOT prevent non-damage effects like Imperial Decree (which creates a trigger on damage), Watcher (banish effect), Smoke Screen or Stupify (might reduction)
• Spells like Void Seeker can still be played and draw cards, but won't deal damage
• If played after Deflect costs are paid (like with Icathian Rain triggers), those costs have already been paid and cannot be refunded