Contrary to most people here I think Zenos is the villain we need. If you hate him and want him to die then he's doing his job. Many of the single player FF games used the same kind of arch nemesis, one that is a true black lunatic with no redeeming qualities, killing indiscriminately, allied to nobody, too powerful to defeat in our first encounters with them, gradually amassing power on their journey to reach a zenith of evil power which they achieve in their final form. This is a very FF antagonist. Important to note that his story is in progress so there may be revelations that alter your perception of him a bit.