How do I attack other players?

To attack other castles, you need troops. Including a hero to lead them can greatly boost the effectiveness of your army. Tap on the castle of a player who you wish to attack and select the attack function. Select the hero and troops in the Set Troops screen, then deploy them to watch them begin their march on your opponent.

Once your troops arrive, the battle will begin. When the battle is over, the surviving troops and hero (if applicable) will automatically return to your castle.