Great job Commander!
Freeing all those islanders is no piece of cake. You can either upgrade your Radar and unlock more clouds and find new opponents or you give your troops a break to celebrate this awesome victory.
You could also join a Task Force and take the fight to the Blackguard!
Also keep in mind that Lt. Hammerman and his evil folks never sleep and will surely try to re-conquer the islands you so courageously freed.It might take a while but over time you will find that your territory has been invaded by the Blackguardonce again.