Because it's not all about the nookie, folks.  'Castle' and Beckett might have finally gotten together in the fourth season finale, but don't expect romance to be the only thing on the detective/writer's plates when the show picks up for season 5.  It seems Beckett will find herself a new enemy in one former 'Heroes' star, but who is the mysterious villain, and what would make him an antagonist to our favorite female ABC detective?

According to TVLine, 'Castle' season 5 has netted itself a new enemy in the form of former 'Heroes' and 'The Office' star Jack Coleman, who will play a “well-liked U.S. senator who finds himself in conflict with Beckett.”  The casting, straight from series creator Andrew Marlowe, comes as a coincidence considering Coleman's last major TV role was a recurring gig on NBC's 'The Office' as Angela's husband State Senator Robert Lipton.

As 'Castle' fans will no doubt recall, Coleman isn't the only antagonist for Beckett in the upcoming season, as season 4 finale "Always" showed Beckett's would-be-assassin Cole Maddox ('Battlestar Galactica's' Tahmoh Penikett) lived to fight another day, vowing to kill the detective again.  It remains to be seen if the character has any ties to Coleman's character.

What say you?  Are you happy to have a familiar face duking it out with Detective Beckett, or would you rather focus on the new-found romance?  Give us your take in the comments below!

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