It just shows that the country established by the Xianbei people in Tuoba Xianbei (that is, the "Great Wei" or the Northern Wei Dynasty) has the dual characteristics of "infiltrating the dynasty" of nomads and farmers. "Khan" and "Son of Heaven" here refer to the same person. This evidence can also be deduced that Mulan did not belong to the nomadic countries further north - Rouran or Turks (although the title "Khan" originally came from Rouran).
Combined with the history of color correction services Tuoba Xianbei at that time, and from the place names "Yellow River", "Yanshan" and "Heitou Mountain" (near Hulun Buir in the far northeast of Inner Mongolia, China) mentioned in "Poems of Mulan", it can be inferred that Mulan participated in this war It happened on the extreme northern border of Tuoba Xianbei, so its opponent can only be the Rouran country that also belongs to the Xianbei people. Tuoba Xianbei was the "Dai Guo" before it entered the Central Plains, and was the most powerful country in the "Desert" (that is, Inner Mongolia and Mongolia now).
After Tuoba Xianbei entered the Central Plains and became the "Great Wei", the desert vacated the sky and was occupied by Rouran, who was originally farther north, and became the strongest rival of Tuoba Xian