Desert Island is the sixth zone in Angry Birds Epic. It contains 5 Levels. 4 Levels proceed in the main story, but the remaining Level is optional. Lots of new desert-type Pigs are introduced here, including:
Here are the Levels of Southern Sea and how to access them:
Desert Island - 1 is the first Level of Desert Island. After obtaining the Yellow Pig Key from Prince Porky and with it opening the Yellow Pig Gate of Desert Island, this is the first Level that shows up.
When Desert Island - 1 is completed, 2 paths open up. One path leads to Eastern Desert Island, and the other leads to Desert Island - 2, which is here. This Level is over looked by 3 bones that look like claws that are rising up from the ground.
This Level is located in-between Limestone Lagoon - 4 and Desert Pig Castle, and is behind a giant rock. A big cactus is near here, too, hinting that you will face some Cactus Knights.
Eastern Desert Island is the only optional Level of Desert Island. The Boss of this stage is a Cactus Knight Captain, who is stronger than a normal Cactus Knight. He can inflict damage-over-time to the Birds and make them suffer damage by attacking a Pig.
Desert Pig Castle is the final Level of Desert Island and is the second Castle overall. It features just about all of the Pigs you have just faced in the previous stages plus some old enemies that you have faced in previous zones. The boss of this Castle is Prince Porky, who deals lots of damage to Birds and ignores high damage.