One of the antagonists has been revealed for the third season of the BBC's modern-day take on Sherlock Holmes, starring Benedict Cumberbatch as the consulting detective and Martin Freeman as his intrepid companion Dr. John Watson.

Lars Mikkelsen – star of hit Danish shows The Killing and Borgen, and the elder brother of Hannibal's Mads Mikkelsen – will play Charles Augustus Magnussen. If you're a member of the Baker Street Irregulars you might just recognise that name from the story "The Adventure of Charles Augustus Milverton" – the name change possibly indicating that Mikkelsen will bring his Scandinavian roots to the role.In Arthur Conan Doyle's story, the title character was a blackmailer who extracted money from wealthy aristocrats (sorry, spoilers but it was written in 1904). The story, collected in the 1904 collection The Return of Sherlock Holmes, was one of the first Holmes stories to be written after Conan Doyle killed off the character at the Reichenbach Falls. But don't expect a straight adaptation – Sherlock has deftly borrowed from the source material in the past, often adapting it in interesting and unexpected ways.The bigger question is whether Magnussen's character will span multiple episodes, becoming the overarching villain of season three. Or will Sherlock's greatest villain, Professor Moriarty, return – yes, he died in the finale of season two, but then again, so did Sherlock.Feel free to speculate wildly below. Or use deduction to guide your inferences. Up to you really.

Daniel is IGN's UK Staff Writer. He adores Sherlock. You can be part of the world's most embarrassing cult by following him on IGN and Twitter