Wei Zhuang, a male character in the domestic animation "Qin Shi Mingyue" series and its sister "Tianxing Nine Songs". Korean, the descendant of the Guigu faction of horizontal swordsmanship, is currently the junior brother of "Mr. Guigu," and "Sword Saint" Gai Nie. One of the founders of the "Quicksand" organization, he was a Korean general, and after the fall of Korea, he led the "Quicksand" to secretly fight against the Qin State and the Luo Wang Organization, and under his management, Quicksand became a professional assassin group that was feared by the world. 
In order to complete the duel between the Guigu ** with the senior brother, he reached a cooperation with the Qin State, and finally completed the duel with Gai Nie in the organ city. Under the persuasion of his friend Zhang Liang, he reached a temporary cooperative relationship of interests with anti-Qin forces such as Gai Nie and Mojia. has been secretly investigating the cause of death of his former friend, Han Fei, the founder of "Quicksand".
There are many reasons why Wei Zhuang turned white overnight: first, he practiced the secret technique left by his master, because the secret technique was extremely complex and dangerous, Wei Zhuang went mad in the cultivation process. This caused serious problems with the flow of qi and blood in his body, which in turn caused his hair to turn gray overnight.
Secondly, Wei Zhuang has experienced many hardships and pressures since he was a child. As a slave and a child in the cold palace, he not only suffered unfair treatment, but also witnessed all kinds of human suffering. These experiences took a heavy toll on his psyche and caused his hair to turn gray early.
In addition, Wei Zhuang experienced Gai Nie's departure when he was a teenager. Gai Nie was his only friend in Ghost Valley and his rival in mind. Gai Nie's departure has left Wei Zhuang with a huge blow and a sense of loss, which may also have contributed to his hair turning gray overnight.
To sum up, the main reasons for Wei Zhuang's overnight whitehead include the cultivation of secret arts, the hardships and pressures experienced since childhood, and the psychological blow caused by Gai Nie's departure. All of these factors worked together to turn Wei Zhuang's hair gray overnight.