I honestly think Dion is the nastiest Windsor (so far Zane MAY give him a run for his money we’ll see) Dion gave very much filthy mouth, BDE, if you like Daddy Emerson then you’ll like Dion. If you have a praise kink this book will very much fulfill you. 
Now the only thing I didn’t like about this book was how both characters allowed their insecurities & fear to not communicate with each other. They would have a great moment & then the next Dion is worried if he’s good enough for Faye & Faye is worried if Dion is like her father, etc. I wished they would’ve been able to communicate those fears & insecurities to each other. 
Also I want to applaud & acknowledge the character growth in Grandma Anne from book 1 (the wrong bride) to this book Luca & Val really forced her to change & its been good to witness.