Vex, Cheerless

Does Vex, Cheerless increase the cost of enemy spells played from Hidden?

Yes, while Vex is in combat, she adds 1 to an enemy spell played from Hidden before discounts are applied.

Playing a card from Hidden ignores its base cost,^[811.1.b] but Vex's increase is applied afterward.^[356.1.b.3] Additional costs or other increases can raise the spell's cost further, and later discounts can reduce it.^{[356.2][356.3][356.4]} This increase does not apply to units or gear played from Hidden because Vex modifies only spell costs.

Does Vex, Cheerless reduce Deflect costs when I play spells?

Yes, while Vex is in combat, her discount applies to Deflect costs when your spell targets an opponent's permanent.

Deflect is a mandatory additional cost.^[356.2.a.2] When your spell targets an opponent's permanent with Deflect, that additional cost is added before Vex's discount is applied.^{[809.1.d][356.2][356.4]}

Vex's discount can offset resources added by Deflect because discounts can reduce additional costs.^[356.4.f] Vex's discount cannot reduce the spell's cost below Vex's printed minimum of 1, but another total-cost discount applied afterward can reduce it further.^{[356.4.d.1][356.4.e]}