Out of this world influence is a very important aspect of the Death Note universe.
Shinigami, their Death Notes, and several other supernatural aspects are major factors in this story. We don't know much about of them, and most of the information we have comes either from the Shinigami themselves (and they can lie) or from the so-called "How to use" rules for Death Note.
Of course, the latter are far from actually being just "How to use", especially with rules such as XXXVI
Rather, these are an attempt to answer some of the readers questions.
A list of them can be found here
http://pwtwtwq.hp.infoseek.co.jp/dea...eath-note4.htm (I don't know how complete it is)
There are two sets of them - one being in Japanese, the other in English.
How different are they?
What exactly do those rules mean, what would happen if ...? Why are some of them so controversial and illogical? Are all of them true? What made the author create such rules?
Please discuss these and other questions regarding anything supernatural in the Death Note here.