If an opponent finalizes Cleave and then you react with Here to Help to play Brynhir Thundersong, does Brynhir's ability prevent Cleave from resolving?

Ruling: Brynhir does not prevent already-finalized cards from resolving. Cleave will resolve normally because the "play" action (putting the card on the chain and finalizing it) has already been performed before Brynhir's trigger resolves.

Sequence:

• Opponent performs the "play" action by putting Cleave on the chain and finalizing it
• You react with Here to Help to play Brynhir
• Brynhir's trigger resolves, preventing opponents from performing the discretionary action "play" going forward
• Cleave resolves normally because it was already finalized before Brynhir's restriction took effect

Nuances:

• "Play" (the action) and "played" (the designation when a card finishes resolving) are distinct terms in Riftbound
• Brynhir prevents opponents from performing the discretionary action of playing cards, but does not stop already-finalized cards from resolving
• This is different from countering, which would prevent a card from being considered "played" at all
• When a card finishes resolving, it is considered "played" for trigger purposes, even if Brynhir is active