When Facebreaker is chained to Stupefy and stuns units with on-stun triggers (like Leona), in what order do the effects resolve?

Ruling: When Facebreaker stuns units with on-stun triggers, those triggers enter the chain after Facebreaker completes and resolve before Stupefy. The controller of the triggered effects chooses their order.

Sequence:

• Facebreaker enters the chain and targets are declared
• Reactions can happen
• The targets are stunned and on-stun triggers are added as pending
• Facebreaker is placed in the trash and considered resolved/played
• The on-stun triggers finalize and enter the chain
• The on-stun triggers resolve (in order chosen by their controller)
• Stupefy resolves

Nuances:

• The on-stun triggers become pending before Facebreaker finishes resolving, but they finalize during the cleanup that happens after Facebreaker resolves