How about a prequel? Focus on how he got to the point where he is now. Like 'Breaking Bad': he starts out as a complete underdog and quite sympathetic, and everybody roots for him - and gradually he grows more and more powerful and less and less human until he is a complete monster. Say he didn't do all of this alone. Say Prometheus started as an organization that resisted Chronos from within (Kind of fitting, since Prometheus opposed Zeus), like professor Odagiri, and gradually they all sacrificed themselves - until Strigoi betrayed the last of them, using as an excuse that this would gain him enough power to defeat Chronos for good, in a perfect Pyrrhic victory: by now, he was as bad as the thing he was fighting.