My Ninjutsu Combines Everything

What should I say? You have to have a good temper to watch this, otherwise you will feel a headache. From the beginning, you will think that there is something wrong with the protagonist's head. The first fused item is neither a knife nor a gun. This is an ordinary book. In the end, the book became something like a little book with the ability to change the content at will. How to say it? It is of no use in the early stage and neither increases combat power nor means. It's just a waste. And the content of that book is also very young. It makes me think that the protagonist was a minor or even only seven or eight years old before he traveled through time. Maybe the age will be lower. After all, the content he came up with is too young. It's not a question of childishness or not, it's a question of younger age. Let me make something like a Teletubbies or a Garden Baby at home. How to say it? I didn't watch this stuff when I was little, I only watched it when I was bored and had nothing better to do. This ability can be used on some completely useless scrap metal, which can be used on a book.