Is “His favoritism toward Daji led to the fall of the Shang dynasty” true?
based on fact
The Book of Documents, 'Oath of Mu,' accuses him of 'heeding only the words of women'; but the primary causes of Shang's fall were the depletion of resources from campaigns against the Eastern Yi and internal divisions, not the bewitchment by a nine-tailed fox as in the novel.
King Zhou (Di Xin)
In official histories, the last emperor of the Shang dynasty is depicted as a ruler who expanded territory but was autocratic and obstinate, while in novels he is portrayed as a tyrannical villain bewitched by a fox spirit.