Does Diane know harlequin is king?

In the context of the story or scenario involving Diane and Harlequin, whether Diane knows that Harlequin is king would depend on the specific narrative details. If the storyline suggests that Diane has insight into Harlequin's true identity or status, then yes, she likely knows. Conversely, if the narrative keeps this information a secret from her, then she would be unaware. Ultimately, the answer hinges on the context provided in the narrative.