I just found the Cartoon Action Hour rpg and I'm going to be using pic related as inspiration for the setting.
Here is my current brainstorm for the setting, feel free to tell me if something isn't working.
"The savage world of Remania lies under threat from the forces of the Skarian Empire, who launch constant attacks from their base on the moon! Led by Emperor Skarian and his inner circle of Dark Lords, the Moon Legions constantly search for the magistones that power their dark Empire! Heroes from across the world take up arms to fight off the Moon Empire while also trying to gain enough power to defeat the multitude of other threats that call the world of Remania home. From the Creeping Hordes of the Living Jungle, to the deadly fury of the Whispering Wasteland, and the voracious appetites of the Burrower, Remania is a place where danger lurks around every corner and the bold, swift and lucky can forge their name into Legend!"