Historic Biography:
Xiahou
Dun was one of Cao Cao's most trusted generals and close relatives along 
with
his younger brother Xiahou Yuan. He lost his eye in the battle of Xia Pei (Pi),
after a duel with Gao Shun, an officer of Lu Bu. Gao Shun retreated, and Dun
pursued. But another officer of Lu Bu, Cao Xing, secretly took aim at the
pursuing Dun with his bow. Xing managed to strike
Dun in the eye-and as Dun pulled the arrow out, he removed his eye as well.
Unable to throw his eye away because of its sentimental value, Dun ate it
instead.
Xiahou Dun dies of illness later on, although the novel claims he died of shock at the sight of Guan Yu's ghost.
Game Biography:
Xiahou Dun is one of Cao Cao's most trusted generals. However, Guan Yu then steps into the picture and ruins everything. Guan Yu, being such an exceptional warrior, repeatedly subdues Wei's attempts to conquer China; however, he earns Cao Cao's favor as he surrenders to Cao Cao after his leader Liu Bei's defeat elsewhere. Xiahou Dun's jealousy consumes him as he repeatedly tries to murder Guan Yu. In the end, when Lu Meng ends Guan Yu, Xiahou Dun sees no other option other than to praise the late Guan Yu's might.