Diaochan (貂蟬) is a character in the Romance of the Three Kingdoms, and may have been a historic figure. She was the adoptive daughter of Wang Yun, an official that was still loyal to the powerless but nominally ruling Han Dynasty. The empire was actually controlled by Dong Zhuo, a warlord who was, even by the standards of the time, cruel and capricious. His chief lieutenant was Lu Bu, who was also a treacherous and vicious man, but who was somewhat saner than Dong Zhuo. Wang Yun asked his adoptive daughter to get both men enamored by her, after which time they would hopefully end up fighting over her. Through a series of manipulations and seductions, she manages to arouse the jealousy of both Dong Zhuo and Lu Bu, finally leading to Lu Bu's assassination of Dong Zhuo. This accomplishment should somewhat be viewed in the light of the fact that neither Dong Zhuo or Lu Bu were paragons of loyalty and foresight. After her role of inciting the two to feuding is completed, Diaochan quickly fades from the text.
To a modern reader, the callousness of Wang Yun sending his adoptive daughter to seduce two men may seem less than chivalric. However, given some of the plots and schemes and just plain cruelty that takes place in the work, it is less extraordinary. In the novel, she actually is the one who requests that she find a way to serve her adoptive father, as well. Little is written about Diaochan, either than that she was young (16, according to the text), very beautiful, very skilled in dancing and singing, and a lot smarter than she seemed at first. Her name probably was a reference to her abilities, since it consisted of the characters for marten and cicada, with "marten" being equivalent to the English "foxy", and cicada referring to her singing ability.
One of the more interesting facts about Diaochan is that the drama surrounding her takes place fairly early in the book, is fairly brief and is fairly unimportant to the plot as a whole. However, in many adaptations of the Romance of the Three Kingdoms, her story is dramatized and emphasized. This is probably due to the fact that on the whole, the Romance of the Three Kingdoms is (despite its name), somewhat short on what we might call romance, instead being a fairly cynical military history. Therefore, the episode of Diaochan's seduction of the two warlords is played up as an episode with more human interest than the battles and betrayals that make up much of the book.