Maybe he has some dark secrets in his past that he doesn't want to be known. For example, he might have been involved in something illegal or unethical that could damage his reputation in the world of the web novel.
It can create suspense. Readers will be curious about what he is hiding and keep reading to find out. For example, it might be revealed gradually through flashbacks or other characters' investigations, which adds an element of mystery to the story.
Maybe he is ashamed of it. Some past works might not be up to his current standards, or perhaps there are elements in the novel that he doesn't want to be associated with anymore.
The player might change the title and his name associated with the novel so that it becomes difficult to trace back to him. He could also use some legal means like copyright restrictions to limit its availability if possible.
On the 'A Journey to the Past' manga wiki, you can expect to see information on the main characters' backstories, reviews and critiques of the manga, and possibly fan art and cosplay inspiration.
The Wiki Fandom for 'A Step into the Past' novel typically has detailed episode breakdowns, background info on the author, and discussions about the story's themes.
Perhaps he has hidden the full extent of his Sage Mode abilities. He might be able to stay in Sage Mode for a much longer time than he has shown so far, or have some other undisclosed powers within that mode, like the ability to sense enemies from much greater distances.
There were many animes in which the male lead hid his strength. Here are some of the more famous ones:
Naruto: Naruto Uzumaki had been hiding his strength throughout the story and only showed it when necessary.
2 One Piece: Monchi D. Luffy Although he was a pirate, he had always hidden his fruit ability until he became One Piece.
[3]" Death ": The King of the Void Ring, Aizen Yuusuke, had been hiding his true strength until he successfully destroyed the Void Ring before he was recognized.
[4. The Attacking Giant: Alan Yeager has been hiding his Giant's Power until he successfully activates it.]
[5: The Blade of Ghost Destruction: Tanjiro had been hiding his talents in the story until he successfully defeated the ghost. Only then did people realize it.]