Best Villain: 3XK
![](https://tv-fanatic-res.cloudinary.com/iu/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1661721234/user/modwild)
Castle and Beckett have faced plenty of murderers over 7 seasons, but 3XK has been the smartest and more formidable of the bunch. That’s what made his return so satisfying. Watching Jerry Tyson play a highly intelligent game of cat and mouse with Castle in interrogation was a highlight of the season.