Sun Ce cursed and killed by Yu Ji

In the novel, there was a man named Yu Ji, which is believed by some to be a misspelling to Gan Ji, who walked around Wu castle for a few days, talking to soldiers and civilians and making them believe he was a magician and healer. Sun Ce, leader of the land that would later be established as 'Wu', grew suspicious of the man. He thought Yu Ji was putting spells on his men, thus he decided to kill him. For this, Yu Ji cursed Sun Ce which eventually led to the latter's death.

Given his activities in the beginning of the second century, some doubt that Yu Ji is not Gan Ji, but another person.

What happened historically?

 * Historically, Sun Ce was killed by the retainers of the former Grand Administrator of Wujun, Xu Gong.


 * Historically, Yu Ji (or Gan Ji) was, of course, not a magician.