Why did L die in Death Note?
He died of a heart attack caused by Rem, who wrote his name in her Death Note to protect Misa from eventually being pegged as the second Kira, as was Light's plan all along.
Because Rem kills him to save Misa. If L continued his 'plans' of testing the death note, they will find out that the 13 day rule is fake, which means that Light and Misa are suspicious again. To stop L from finding out that Misa and Light are Kira, Rem needed to kill L. And Light knew it all along.
I feel that's an incomplete question. but if u look at from the death note prespective, you would die if any shinigami writes ur name in his or her note book and this all because that shinigami wants to increase its life span... so my friend if u die don't worry, because of your death and shinigami can live......