If Smokescreen is cast on attacking Vayne (reducing her from 5 Might to 1 Might), and she survives by removing the defender, then moves to another battlefield with Ride the Wind where there's a defender, what is Vayne's Might in the new combat?

Ruling: Vayne will be 1 Might in the new combat. Smokescreen snapshots the Might reduction as -4 when cast and applies it continuously for the rest of the turn, regardless of whether Vayne's Might calculation temporarily goes negative.

Sequence:

• Smokescreen is cast on attacking Vayne (5 Might: 2 base + 3 Assault)
• Smokescreen snapshots -4 Might reduction and applies continuously
• Vayne leaves combat, losing Assault bonus: 2 (base) - 4 (Smokescreen) = -2 Might (treated as 0)
• Vayne moves to new battlefield with Ride the Wind and becomes attacker again
• Vayne gains Assault bonus again: 2 (base) + 3 (Assault) - 4 (Smokescreen) = 1 Might

Nuances:

• The -4 Might from Smokescreen does not change once snapshot, even if the unit's calculated Might goes below 0
• When a unit's Might is less than 0, it is treated as 0 for all purposes, but the underlying value remains negative for calculation purposes
• A unit with negative Might won't die unless it takes damage