Does Fiora Legend trigger when Sett enters play as a 4 Might unit that becomes Mighty through his buff, and does she trigger again when Sett uses his activated ability (spending the buff to become 4 Might, then gaining +4 Might to become 8 Might)?

Ruling: Yes to both situations. Fiora Legend triggers when Sett enters play as a 4 Might unit before his When You Play Me buff resolves, and she triggers again when Sett uses his activated ability.

Sequence:

• Sett enters play as a 4 Might unit
• Fiora sees him as 4 Might and can trigger
• Sett's When You Play Me buff then resolves, making him Mighty
• When Sett activates his ability, you pay the buff cost (making him 4 Might)
• The ability goes on the chain
• Cleanup happens while he's at 4 Might (Fiora can trigger)
• The +4 Might resolves, making him 8 Might and Mighty again