How did Emperor Xiaowen, who killed his own son, destroy the Northern Wei Dynasty?

First of all, I think this question is irrelevant. Emperor Xiaowen killed his own son, but this has nothing to do with his ruin of the Northern Wei Dynasty. Emperor Xiaowen even killed his own son, which only shows that he is a heartless man. He destroyed the Northern Wei Dynasty because of his own life-long mistakes in governing the country. He struggled for the separation of Xianbei and Han descent all his life.

He ascended the throne when he was very young. At that time, he had no ability to handle government affairs, so he had to rely on his grandmother, the then queen mother. At that time, in order to adapt to the situation, the Queen Mother carried out reforms and put forward the salary system, which overthrew the previous habits of nomadic people, that is, those who served as officials in the DPRK were not allowed to receive salaries, and salaries needed to be plundered. After that, the Queen Mother carried out a series of reforms, such as abolishing Xianbei witchcraft, respecting Confucius and prohibiting intermarriage.

Emperor Xiaowen, who lived under the protection of Empress Dowager Cixi since childhood, is very similar to Empress Dowager Cixi in thought. After the death of Empress Dowager Cixi, Emperor Xiaowen came to power, but these reforms still did not stop. Under Emperor Xiaowen's rule, the imperial court went to Xianbei with increasing intensity. Emperor Xiaowen not only moved the capital to Luoyang, but also vigorously promoted the sinicization and writing of Chinese characters throughout the country, and encouraged Xianbei people to marry Han people.

This extreme practice of suppressing Xianbei people met with great resistance from Xianbei people. Because the prince colluded with Xianbei nobles in the political reform, Emperor Xiaowen was worried that the prince would split Xianbei and Han nationality, so he demoted the prince to Shu Ren. After that, the prince still refused to give up and wanted to rebel, and was executed by Emperor Xiaowen. This is not the direct cause of the demise of the Northern Wei Dynasty, but the ultimate cause of the demise of the Northern Wei Dynasty is that Emperor Xiaowen's reform is too radical and he does not know how to be flexible.