East Hyrule is a big desert land, with very hot climate. There are many castles, but most of them are almost destroyed by Evil Forces of Ganon.
Originally it was the part of Hyrule, ruled by the King. But when Hyrulian Civil War started, most of territories became the parts of Squadala Empire. The king had no choise and gave East Hyrule to Squadala Man.
During the test phase of Napoleon's Revival Machine, most of East Hyrule, along with France and Belgium, was destroyed in a zombie invasion.
Several years ago, East Hyrule was invaded by Hitler's army. During the invasion, Link led a siege on the Nazi bases, blowing them all up with bombs. Morshu has supplied these bombs for him and planned to use them on the world. However before he was able to detonate them, he was squashed by Squidward's House. Instead of getting a new leader, Squadala Man took complete control over East Hyrule, and quickly drove out the Nazis using the power of Cheese.