If I have Fiora Victorious in my base equipped with a Bf Sword, then someone uses Falling Star. It resolves dealing 6 damage to my 7 might. If this resolves and then the other person uses an action spell that reduces Fiora's might by 1, does Fiora die?

Yes, Fiora, Victorious will die in this scenario.

Here is the breakdown of why this happens based on the rules for damage, Might, and the "Mighty" keyword.

1. The Situation Before the Spell

• Fiora, Victorious has a base Might of 4.
• She is equipped with B.F. Sword, which provides +3 Might.
• Her total Might is 7. Because 7 is at least 5, she is Mighty.
• While Mighty, she gains Shield, which adds an additional +1 Might while she is a defender. (Note: Since she is in your base, not defending, this +1 does not currently apply.)

2. After Falling Star Resolves

• Falling Star deals 6 damage to Fiora.
• Fiora now has 6 damage marked on her. Since her total Might is 7, she remains on the board with 1 "health" (7 Might - 6 damage = 1) remaining.

3. After the Might Reduction

• The opponent plays an action spell that reduces Fiora's Might by 1.
• Your total Might drops from 7 to 6.
• She is still Mighty (6 is ≥ 5), but her total Might is now 6.
• Because she still has 6 damage marked on her, and her new total Might is 6, she has taken lethal damage (damage equal to her current Might).

Why she dies:

According to Rule 710, units on the board are always evaluated according to their current Might. When a unit has damage marked on it that equals or exceeds its current Might, it is destroyed. Because the reduction in Might brings her total Might down to the exact amount of damage she has already taken, she is immediately destroyed.

Note: This is my interpretation based on the standard rules for damage calculation and Might thresholds (Rule 710 and Rule 471). While no specific FAQ exists for this exact chain of events, it follows the established layer system and damage interaction rules.