https://www.looper.com/1361581/castle-vs-rookie-nathan-fillion-settles-debate/

Nathan FIllion finally settles a huge fan debate regarding his characters in both "Castle" and "The Rookie." Here's what the actor had to say.

Nathan Fillion was so burned out at the end of Castle. You can see his physical transformation from the beginning to the end.

He got himself together for The Rookie.

He made The Rookie an ensemble so he doesn't have to be in every scene.