Leon is kind of an oddity in the series, he is kidnapped by the Empire but eventually decided to side with them and even try to take over. Yet eventually sides with the party when the Emperor returns as the Demon King. So why do you think he makes the choices he did.

Note, this thread is not about pointing out the limitations of the storytelling aspect of the game due to it's humble origin but rather I'm curious to see how you would rationalize his actions? Was he brainwashed to be evil? Got corrupted by the power of the empire, or was he trying to end all wars by uniting the world under one banner?