The new regulations have created 'a devil of' a problem [=a very difficult problem] for many small businesses.
He had 'a devil of a time' getting another job. [=he found it very difficult to get another job]
The shoes look great, but they're 'the devil' to walk in. [=they are very difficult to walk in]
(..) Can be deadly. You don't say. Just out of interest, is there any other way out of here? No. What the devil are all you doing down here? Thieves! You gave up the..... -Imperio -You! (..)2011 Harry Potter and the Deathly Hallows: Part 2