Tap the Hero's portrait to activate their Legendary Power. Powers won't be availabe again until after a cooldown period. Heroes are knocked out when they run out of Health. A knocked out Hero is unusable for the remainder of the quest. Use your gold to upgrade Heroes to prepare them for later Quests. Legendary Powers come in two types. Green Legendary Powers support or help your Heroes while on a Quest.. Tap the Legendary Power icon to activate. Red Legendary Powers are offensive effects or attacks that target enemy units. Tap the Legendary Power icon to activate. Both types require cooldown after use.