Complex sentence: Frank eventually discovers that an elusive organization called "Obscuris" is in the city looking for a monstrous creature known as "Calder" and reunites with Vick on a few occasions, but their opposing views prevent them from working together.
Split into simpler sentences: Frank eventually discovers that an elusive organization called "Obscuris" is in the city looking for a monstrous creature known as "Calder". He also reunites with Vick on a few occasions, but their opposing views prevent them from working together.