The 1st 2 seasons were really fantastic and were a continuation of the same timeline.
This season jumps ahead into the future, and without having read the original manga, the story is very confusing for the 1st half of the season. Various MAJOR changes have taken place without any explanation or context regarding integral (and much loved) characters which is extremely confusing and ultimately leads to initial frustration. What makes matters more challenging is the change in animation style, with various characters looking different.
This is probably why the reviews for this season are so mixed! And to be honest, I originally gave this season a 5/10. I was very annoyed at where the series had gone.
That being said, the 2nd half of the season is much much better. The story has loads of pay-offs that you're hoping for and the story is very engaging. Character archs come to fruition in mostly satisfying ways and the season as a whole was ultimately very enjoyable. I thought the main villain was a little weak to be honest, but there were many secondary bad guys that were very memorable, particular the priest.
I enjoyed this season far more on 2nd viewing as I understood the various characters better and could follow the story arch in more depth.
At the end, after 2 viewings, I believe this season is a high 7, even 8 out of 10. With season 1 and 2 being high 8s or 9s.
