I really enjoyed season 3.... although that finale was very crazy.... Spoiler The Mad King Dusk ending felt a little too over the top, but I'm still interested to see where Empire goes. Someone else who read the books can correct me, but I believe the face of the Mule was also a ruse and was secretly someone else the entire time.
I really enjoyed it, it was a a great finale. Spoiler To answer your question, in the books Magnifico was the Mule if I remember correctly. In the show they changed it to the social media girl it seems. I would guess next season will pick up right after this season, or a small jump in years, rather than centuries.
im glad Apple just lets its shows run in the background. any other network would have cancelled it. Im ready for the next season!