Complex sentence: Although Rumpelteazer and Mungojerrie work for Macavity, they're not as malevolent as their boss cat: in fact Rumpelteazer and Mongojerrie behave more like clowns than criminals, and are of the most important members of the Jellicles.
Split into simpler sentences: Although Rumpelteazer and Mungojerrie work for Macavity, they're not as malevolent as their boss cat. In fact, Rumpelteazer and Mongojerrie behave more like clowns than criminals, and are important members of the Jellicles.