Why did Shan Zhi read Illustration of Devil's Fruit?

In the past 100 years, Robin has made great achievements in the study of blank historical texts. In those 100 years, there was indeed a prosperous country. Unexpectedly, the devil fruit was discovered and studied at that time, but this force, which was most hated by the sea, was not allowed to be used casually in that country. Because of this, the country was destroyed by the later world Coalition government. At that time, in the final stage of the battle, the king of the country did not listen to the opinions of the soldiers called "demons" and gave up using the last fighting force "ancient weapons" created by "demons" because it would probably cause the destruction of the world. In the process of studying historical texts, I found a mysterious figure who always followed the straw hat pirates, and was finally caught by Shan Zhi's design. This mysterious man claims to be a descendant of the inferno, and Shan Zhi is the prince of the inferno! ! When Shan Zhi was a child, in order to avoid being hunted by the world government, he was forced to travel around with Shan Zhi as a baby, so Shan Zhi didn't know where his birthplace was, and Shan Zhi, a folk story from all over the world, was also heard. As an outstanding work of the demon family, The Demon Fruit Atlas was asked by Shan Zhi to record the appearance and function of all fruits. (Later, I don't know how to show it to Blackbeard) Later, in an accident, Shan Zhi was taken in separately by the chef of the passenger ship when he was hungry. . . But the atlas I saw and the stories I heard in my childhood are deeply imprinted in Shan Zhi's memory. It is precisely because of the special physique of the demon clan that the photos taken by Shan Zhi to issue a wanted order in the First Seven Waters War show the terrible outline of the demon. . . . The mysterious man resented the king for not using "ancient weapons", but Robin agreed that "people can't be seen on the map". Shan Zhi destroyed everything, so what's the point of the kingdom? "In the end, the mysterious man entrusted Shan Zhi to" seal the ancient weapons forever as a demon prince ".