Fitting rules of Death Note There are at least 130 rules of use of the Death Note. Do they all fit on the one last page of the notebook (how?) or do they come from some other source? Was it ever addressed in the manga or the anime?
The Death Notes originally do not have any rules written on them. Ryuk dropped a Death Note in the human world because he was "bored", so he only wrote enough rules to get a human interested in it (and he wrote them in English, the most common language). During the course of the plot, Light infers several rules not written in the book through his experiments. (Even Ryuk admitted once he did not know of one such rule.)