In Empires & Puzzles, ALL Defense Teams (whether it be in Raid battles, Raid Tournaments, Wars, Map stages, etc.) are controlled by a very basic AI.
This AI does not have the ability to make thoughtful strategic decisions; for example, it will always choose targets at random, and will always immediately fire Special Skills when they become available. You may have seen enemy Defense Teams make such silly "mistakes" in battles.
To compensate for the AI's lack of tactics, all Defense Teams — INCLUDING your own! — are always given a few advantages when facing off against a player-controlled team. This includes all of its Heroes receiving a small amount of mana each turn.