Complex sentence: His main antagonist is Dr. Erich Nazō (ナゾー), the leader of a crime syndicate bent on world domination who wears a black costume and mask with bat-like ears.
Split into simpler sentences: His main antagonist is Dr. Erich Nazō (ナゾー), the leader of a crime syndicate bent on world domination. Nazō wears a black costume and mask with Batman-like ears.