Siobhan Finneran
Siobhan Finneran, who played the scheming maid, on "Downton Abbey." PBS

Siobhan Finneran won't return for the fourth season of "Downton Abbey," creating an unsatisfying conclusion that will leave fans disappointed.

“I'm not doing any more," Finneran told the Huffington Post UK. "[Sarah] O'Brien is a thoroughly despicable human being -- that was great to play.”

Finneran will appear in the second season of BBC1’s “The Syndicate,” as a nurse whose fortunes turn after she and coworkers win the lottery. The news was confirmed by a Masterpiece Theatre spokesman.

O’Brien’s departure won't be as shocking as the deaths of Lady Sybil Crawley (Jessica Brown Findlay) or Matthew Crawley (Dan Stevens), but it will come as a surprise, considering her role as Cora Crawley’s maid, and her villainous relationship with Thomas (Rob James-Collier). During the third season, O’Brien and Thomas went from allies to enemies; at one point on the show, O’Brien tried to get Thomas fired. O’Brien also had plenty of secrets, including causing the miscarriage of Cora Crawley in season two.

Unfortunately for fans, O’Brien will never be redeemed or meet an end fitting of her villainy. As previously reported by IBTimes, it was leaked before the end of the third season of “Downton Abbey” that neither Findlay nor Stevens would return for the fourth season. The show's creator, Julian Fellowes, and producer, Gareth Neame, said British actors tend to be signed to three year contracts for a series, and, unlike their American counterparts, they tend to tackle multiple projects and not stick around for long stretches of a show. The departures of both Stevens and Findlay were well known in advance, and Fellows was able to create storylines that led to the deaths of Lady Sybil and Matthew.

Although Finneran's character was only a servant, she was cast as a villain, alongside Thomas, who became a sympathetic character, but there will be no such arc for Finneran’s character. It seems as though O’Brien will be unceremoniously written off as “Downton Abbey” returns this season.