Some of the more powerful abilities require time to be fully activated. When an enemy hero begins casting such a spell, you will receive a notification, and a bright magical effect will be displayed over that hero on the battlefield. Another notification will appear when the spell comes into effect.
If it has a given duration, its icon will appear in the ‘Enemy Abilities in Effect’ list on the side of the screen, with a countdown timer showing its remaining duration.
Certain hero skills and spells have casting time: this is the amount of time that it takes the skill to take effect after activation.
Spells and skills that have casting time can be breached. If the caster or skill user is disturbed while activating the spell or skill, he won’t be able to finish. The caster is only disturbed if he suffers a hit that equals at least 10% of his HP.