What do you think of the historical text of the last road sign of One Piece, which was buried in Fisherman's Island for 7 years?

The title of One Piece is Roger's Adventure, so this sentence is mainly about Roger's pirates. It tells the story of Roger's pirates who finally landed on the final island after many adventures. Roger finally became the first one piece to travel around the world. On the final island, Roger learned the historical truth of blank 100 years and finally found the legendary treasure, because Roger was the first person to board the final island.

As we all know, in order to reach the last Rafdru Island, we must collect four historical texts of road signs, and Roger's four historical texts, first from Narcissus Sing Tao, then from Aunt, got another historical text in ZuoKirishima, but there are only three such historical texts. So where is the last historical text of the road sign?

Through this story, we found the answer. After Roger left the empty island, he went to Shuidu to find Tom first. We know that Tom is a boatman, so Roger should have something to do with the ancient weapon "Pluto". After leaving Shuidu, they went to Mermaid Island again. In the marine forest of Mermaid Island, they found two historical documents, one of which is blue, and that is Joy Boy. The other piece is a red historical text. Through historical texts, Roger knew that Poseidon, an ancient weapon, was a mermaid princess, and through Li Xia, he also knew that the mermaid princess would be born in 10.

It seems that Mermaid Island is the only way to become one piece. Then Luffy must come to Mermaid Island again, and the foreshadowing that Ota was buried for seven years will be revealed. At that time, the fisherman's fortune teller Sha Li predicted that Luffy would cause the destruction of the entire mermaid island, and Sha Li's prediction was very accurate. She predicted that the white beard would die and the mermaid princess would be born in 10 years, which was confirmed.

However, Luffy obviously won't destroy Fisherman's Island. However, Luffy once fought with her because her aunt ate her dessert, and she was also embarrassed by Luffy and others. If Luffy returns to Fisherman's Island again, maybe Luffy will declare war on her again, then her aunt may be angry with Fisherman's Island, thus causing a devastating blow to Fisherman's Island.

How to treat the historical texts of Mermaid Island?