Complex sentence: Jedah was unofficially named "Belial Jr." while "Vampire Savior" was in development, and the working title of the U.S. release was "Jedah's Damnation".
Split into simpler sentences: Jedah was unofficially named "Belial Jr." while "Vampire Savior" was in development. While the U.S. release of "Vampire Savior" was still in production, its working title was "Jedah's Damnation".