If you have Vex Cheerless which reduces cost of your own spells by 1 power and 1 energy, and you use a spell which costs 3 energy, but target a unit with Deflect, do you just pay 2 energy and avoid the cost of choosing the unit?

To answer your question, we must look at how costs are finalized and how Vex, Cheerless interacts with mandatory costs like Deflect.

According to RiftJudge FAQ #8596 and FAQ #9668, you do not simply pay 2 Energy and ignore the Deflect cost. Here is the step-by-step breakdown of how your final cost is calculated:

1. Start with Base Cost

• Base Cost: 3 Energy.

2. Apply Additional Costs (Deflect)

• Deflect: This is a mandatory additional cost. If the unit has Deflect 1, you must add 1 Power to the cost of the spell.
• Current Total: 3 Energy + 1 Power.

3. Apply Discounts (Vex, Cheerless)

• Vex, Cheerless: Her ability reduces the cost of friendly spells by 1 Energy and 1 Power (down to a minimum of 1 Energy).
• Calculation: (3 Energy + 1 Power) - (1 Energy + 1 Power) = 2 Energy + 0 Power.

Final Result

You must pay 2 Energy. You do not avoid the cost of choosing the unit; rather, the Deflect cost (1 Power) is added to your spell's total cost first, and then Vex's discount is applied to that new total. This effectively offsets the Deflect cost, leaving you to pay the discounted base cost of the spell.

Key Nuances:

• Mandatory: Deflect is a mandatory additional cost that must be included in your cost calculation before any discounts are applied (Rule 356.4 / FAQ #8596).
• Minimums: Vex's "minimum 1 Energy" restriction applies only to the spell's base cost, not the total cost including additional costs. Because your final cost is 2 Energy, this requirement is satisfied.
• Order of Operations: Per Rule 356.4, discounts to the total cost are applied after all additional costs have been summed.