Does Ezreal's ability allow paying 1 energy instead of a power to equip gears?

Question

Accepted Answer

No — under the Core Rules you cannot spend Energy to pay a Power cost unless a card or effect explicitly allows you to do so. I don’t have the exact text of Ezreal's ability, so if that ability explicitly permits spending Energy in lieu of Power, that specific allowance would override the general rule.

By default, Power costs must be paid with Power from your Rune Pool and Energy cannot be substituted for Power. Only an effect that explicitly grants the option to spend Energy instead of Power (or that changes how costs are paid) would permit that substitution. If Ezreal's ability does not explicitly allow spending Energy as Power or otherwise change the payment rules for equipping gears, you may not pay 1 Energy instead of 1 Power to equip gears. [131] [165.2] [356.6] [429.3]

Check the exact text of Ezreal's ability. Look for explicit language that lets you spend Energy instead of Power or that changes how equip costs are paid. If the ability explicitly says you may spend Energy in place of Power (or allows paying gear equip costs with Energy), then that effect permits the substitution despite the default rules. If the ability does not explicitly allow spending Energy in place of Power, then follow the default cost rules: pay Power costs with Power from your Rune Pool and Energy costs with Energy from your Rune Pool. [131] [165.2] [356] You may use Add Reactions to add Power during the Pay Costs step if you need more Power to pay an equip cost, but that is adding Power, not spending Energy as Power. [357] [429.3]

If another card or ability adds Power to your Rune Pool as a Reaction during the Pay Costs step (e.g., an activated Add Reaction), you may use that Power to pay the equip cost even after initiating the play/activation [357.1.a] [429.3]. If an effect changed how costs are paid or replaced a Power cost with a non-standard cost, that replacement could allow other payment methods, but such an effect must be explicit on the card. Also note effects that reduce or set costs operate on printed costs for checks (see example involving Sky Splitter and Lux, Illuminated) [131.4].

Default rule: Energy and Power are distinct components of costs and must be paid from the corresponding resource in your Rune Pool. The printed Cost shows Energy and Power separately; Energy Cost is the numeral and Power cost is the symbols [131]. Players must first add Energy and Power to their Rune Pool before spending them to pay costs [165.2]. Costs may be Energy costs or Power costs or non-standard costs; Power costs are a distinct component and are paid with Power [356].

During the Pay Costs step, a controller can activate Reaction abilities that Add resources to put Energy or Power into their Rune Pool to pay those costs, but that is adding the appropriate resource — it does not convert Energy into Power or let you substitute Energy for Power unless an effect explicitly allows it [357.1.a] [429.3]. An Add Reaction that adds Energy cannot be used as if it added Power unless the effect text specifically says so.

Therefore, unless Ezreal's ability explicitly says you may spend Energy instead of Power to equip gears (or otherwise replaces the Power cost with an Energy cost or a non-standard cost), you cannot pay 1 Energy in place of 1 Power to equip gears. If you provide the exact text of Ezreal's ability I can give a definitive ruling for that specific wording.