In Shadow Fight, Energy granted the player permission to do battles. It could be replenished after waiting for a certain period of time, by receiving Energy Boosts, by using Energy Potions or by paying rubies. The maximum amount of Energy a player could have was the player's level + 100, with the maximum number of energy increasing by 1 every time the player leveled up.
Waiting. - 1 Energy Point could be earned after every 2 minutes. This method was free but it took a long time to get many Energy Points.
Energy Potions. - If players did not wish to wait, they could use Energy Potions. Energy Potions could be earned from completing battles or could be bought from the Shop under the 'Items' category using rubies.
Energy Boosts - Players were able to receive energy boosts from their friends who played the game as well. To send an energy boost, players had to click on the Gift icon and select a gift. Then, the player were shown a list of friends they could send the gift to.
Rubies - If players were all out of Energy Points they could use rubies to pay for them.