If Fiora has a buff making her Mighty (5+ might) and opponent's Ahri Inquisitive moves into her (reducing might by 2), does Fiora gain +1 from shield before losing Mighty, or does she lose Mighty instantly?

Ruling: Fiora loses Mighty instantly and does not gain the +1 from shield. When checking layers with the Ahri trigger applied, Fiora starts at base 4 might, gains +1 from her buff, then loses 2 from Ahri, ending at 3 might - never reaching the 5 might threshold needed to activate her passive abilities.

Sequence:

• Check trait altering layer (N/A in this case)
• Check ability altering layer: Fiora is at base 4 might, so her passive ability is not active yet
• Check arithmetic layer: Apply +1 from buff first (increases before decreases), then -2 from Ahri trigger, resulting in 3 might
• Loop back through layers - no changes occur
• Final result: Fiora is 3 might with no passive abilities active

Nuances:

• Deflect cost must still be paid when the Ahri trigger targets Fiora and finalizes to the chain, before the ability resolves and removes deflect
• Once Ahri's ability resolves, no further items targeting Fiora need to pay deflect costs until end of turn
• Layers are checked in order (trait altering, ability altering, arithmetic) and loop until no changes occur
• Within arithmetic layer, increases are applied before decreases