Read: Nathan Fillion Reacts to 'Castle' Ending: 'Mic Drop' Fillion will be Simon Williams, aka Wonder Man, who has a long history in the Marvel Universe, dating back to the early 1960s.

Actors Nathan Fillion and Stana Katic were once reportedly at odds with each other on the set of Castle. Neither have corroborated the reports. But if there’s one thing the two actors didn’t ...

“Stana Katic and Nathan Fillion completely despise each other. They will not speak when they are off set, and this has been going on for seasons now,” the insider told Us.

With the news of Castle’s cancellation after eight seasons, here’s everything that happened behind the scenes between Stana Katic and Nathan Fillion — take a look back!

Almost 24 hours after the news broke that ABC’s Castle would not be asking back Stana Katic for a possible Season 9, series star Nathan Fillion has offered his first thoughts on his leading lady ...

Hooray for flow! Stana Katic also confirmed it, "Oh yeah, the end of this season you guys are going to be happy." She repeated with a coy laugh, "Any Caskett fans out there: You will be happy ...

Katic has starred in "Castle" alongside Fillion since 2009. Though the show has not yet been renewed for a ninth season, ABC confirmed that Katic and Tamala Jones, who plays Lanie Parish, will not ...