Complex sentence: There was an inconsistency on how many mutants were actually on Third Earth; some episodes had a small army guarding Castle Plun-Darr, but in most episodes, only Slythe, Monkian, Jackalman, and Vultureman were seen.
Split into simpler sentences: There was an inconsistency on how many mutants were actually on Third Earth as some episodes had a small army guarding Castle Plun-Darr. But in most episodes, only Slithe, Monkian, Jackalman, and Vultureman were seen.