Call it fate. This dagger could have prevented the Three Kingdoms Era from happening altogether had it accomplished its most famous task.
In the time when Dong Zhuo 董卓 the tyrant took control of the Han dynasty, various warriors and ministers loyal to the Han empire plotted to murder Dong Zhuo and rescue the world from descending further into hell. One of them was none other than Cao Cao 曹操. At that time a mere minister with little repute and no army, Cao Cao wanted to do his part to save the Han dynasty. He approached Si Tu Wang Yung 司徒王允, one of the ministers of the court also planning on murdering Dong Zhuo, and told him of his intentions. Wang Yun suggested that Cao Cao utilize Dong Zhuo's greed for treasures, then lent to Cao Cao the Seven Star Dagger for this very purpose.
As Cao Cao approached Dong Zhuo, he came very close to putting an end to the tyrant when Dong Zhuo sends his bodyguard, Lu Bu 吕布, away to fetch Cao Cao a horse. Dong Zhuo lies down and back faces Cao Cao, the perfect opportunity for the attack! As Cao Cao pulls out the dagger from its sheath, Dong Zhuo suddenly sees what is happening via a mirror on the wall. Dong Zhuo turns round and confronts Cao Cao, just as Lu Bu returns. Panicking, Cao Cao knelt down and pretended that he was there to present this beautiful dagger as a gift. Dong Zhuo accepted, but found Cao Cao's behaviour unsettling. Cao Cao then quickly left and never came back for fear of his life.