Rigor Mortex is a monster that was created to overpower the ruler of the island, Leonyx. It reflects the desires of whatever it faces, according to its creator, Zehlam. This caused it to reflect his greed and hatred and turn on all of humanity. This monster searches eternally for anybody that understands 'real strength' and it 'becomes one' with those that simply do not understand. When it is finally encountered in the Dark World, it desires to become one with you as well and escape from the Dark World so that it can destroy the world.