Power serves as both the stamina and attack value of a Z/X during battle. When a Z/X attacks another Z/X, it deals damage to the opposing Z/X equal to its Power. If a Z/X received damage equal or higher to its Power in a turn, or if its Power is reduced to 0 or less, it is destroyed per Rule Effect.
208.1 The stamina and the value of damage amount in battle (600) of a card. This parameter is only possessed by cards with Z/X, Z/X Extra, and Z/X Overboost as their type.
208.2 During priority preprocessing (702), if the damage that a card receives is equal to or greater than its own Power, or if its Power is equal to or less than 0, this card is destroyed per Rule Effect (904).
208.3 During battle, if a card deals damage to a Z/X due to attack, it deals damage equal to its own Power (604.3).