Can Captain Miss Fortune use Gust in response to becoming a defender (after moving and readying a rune) but before Shield and Master Yi Legend passives apply?
Ruling: You cannot respond to becoming an attacker or defender because it is not a trigger. However, you can respond to Miss Fortune's on-move trigger (which happens before combat begins) to play Gust on the Poro, but this requires having an already-ready rune available.
Sequence:
- Miss Fortune moves to battlefield
- Miss Fortune's on-move trigger goes on chain (readies a rune)
- Players can respond to this trigger (this is when you could play Gust if you had a ready rune)
- Trigger resolves
- Combat begins and units become attackers/defenders
- "When I attack" and "when I defend" triggers go on chain (units are already designated at this point)
Nuances:
- The rune readied by Miss Fortune's on-move trigger cannot be used to pay for Gust during the response window to that same trigger, since it hasn't resolved yet
- You would need a different already-ready rune to make this play work