This morning, Sherlock series producer Sue Vertue revealed a photo of series 3’s enemy: Charles Augustus Magnussen.

Charles is played by Lars Mikkelsen, known for roles in Those Who Kill, Flame and Citron, and King’s Game.

It’s likely that the role is based on the character Charles Augustus Milverton seen in one of Arthur Conan Doyle’s Sherlock short stories published in 1904. The character is “the king of blackmailers” and “causes Holmes more revulsion than any of the 50-odd murderers in his career,” according to the character’s Wikipedia entry.

Here’s a photo of Mikkelsen in the role:

Related: See the first official photo from series 3 featuring Sherlock and Watson!

Sherlock series 3, episode 3 begins filming this week in Cardiff. The title of the final episode is “His Last Vow,” and it’s likely that Charles has a big role in the finale because the announcement of his casting was timed with the start of episode 3 filming.

Even though the enemy character may not be well known in the Sherlock world, television series creator Steven Moffat pointed out at San Diego Comic-Con earlier this month that Doyle’s wealth of writing offers them a wide array of content to use. Check out more of what we learned from the Sherlock.

Sherlock series 3 premieres in early 2014 in the United States, and sometime later this year in the United Kingdom.