The brother of Felicia Epstein, Leon went missing five years before the events of the story. Through a message given to android 1019, Leon reveals to Felicia that he is living in the post-war utopia city of Oz, and invites her to come join him.
Upon arriving in Oz, it is revealed that Leon has suffered a mental break and intends to use Oz and its technology to control humanity through warfare. To achieve this, Leon has connected his brain to Asura, the main computer of Oz, which also controls a deadly laser that can be fired from space at any moment. After his plan is thwarted by Felicia and Mutou, Leon transfers his conscious to the body of a child but is killed by one of his own android creations.
