If Ahri - Inquisitive's triggered ability is forced to target a unit with Deflect (like Qiyana) as the only valid target, must the Ahri player pay the Deflect cost (recycle a rune), or can they decline?

Ruling: You can choose to decline to pay the Deflect cost, and if you do, Ahri's trigger will not go on the chain and will be removed.

Sequence:

• Ahri's ability triggers when Qiyana moves to the battlefield
• Qiyana is targeted (as the only valid target)
• Deflect causes Ahri's trigger to incur an additional cost
• The player may decline to pay this cost
• If declined, the trigger ceases being a pending item and is removed from the chain

Nuances:

• Players may decline to pay for triggered abilities that have incurred a cost
• It is Ahri's trigger (not Deflect itself) that has incurred the cost, which allows the decline option
• This applies even though Ahri's ability does not say "may" and even though Deflect is a mandatory additional cost