'Sherlock' season 4 spoilers: new details on baddie Culverton Smith, episode 3 and new characters

New details about the villainous character to be played by Toby Jones in "Sherlock" season 4 have been revealed in the latest issue of Crime Scene Magazine.

As fans already know, Jones will bring to life Culverton Smith, a tropical disease expert from Sir Arthur Conan Doyle's short story, "The Adventure of the Dying Detective."

Co-creator and executive producer Steven Moffat revealed that the "Sherlock" season 4 baddie will be "completely different" from the enemies that Sherlock Holmes (Benedict Cumberbatch) has encountered.

"He's the darkest villain we've had," Moffat described Smith in the magazine (scans provided by Twitter user, SherlocksiPod).

"There was always something charming and engaging about Moriarty. There was something fascinating and actually amoral, rather immoral, about Charles Augustus Magnussen. But this guy is the purest evil. Sherlock is even appalled by him. He's the most evil villain we've had. I don't think that when you see it, you'll disagree. He's horrific," he went on to say about Jones' character.

Smith will appear in the second episode of "Sherlock" season 4, "The Lying Detective." Since it is based on the aforementioned story, it is safe to say that Smith and Sherlock will know in the end who is the better liar of the two of them.

The inclusion of Smith in "Sherlock" season 4 is what makes this season ultimately the darkest the show has had. However, it won't be as sinister with the involvement of a baby and a canine.

It was revealed that the first episode, "The Six Thatchers," was originally titled "The Three Watsons" with the addition of Mary (Amanda Abbington) and Watson's (Martin Freeman) child.

Co-creator Mark Gatiss teased that the "Sherlock" season 4 premiere was tentatively called as such because the baby changes the dynamic and puts the characters in a "different place."

The magazine also revealed that a dog will be featured in the new season. This pooch is believed to be Toby from "The Sign of the Four," another regarded Conan Doyle story.

Meanwhile, it was revealed last month in a leak that the "Sherlock" season 4 finale will be titled, "The Final Problem," a work by Conan Doyle that centers on the ultimate showdown of Sherlock and his nemesis, James Moriarty.

"Sherlock" season 4 will premiere on Sunday, Jan. 1, 2017, at 9 p.m. ET on PBS.