How do you declare war on another Alliance in DDE?

R5 or R4 members of an alliance can declare war. You will have a truce time setting for your alliance which determines when you will be able to declare war or be declared upon. When your time slot is active, open the Doomsday War Alliance Duel screen from the events menu and check the list of alliances in your group. You will need to find an alliance in your group that is available for you to declare ward on. The list will show you their status and if they are available then you will see a button to declare war on them.