Well, one of the main plot points is the emergence of new Death Notes and new users. There are different individuals who get their hands on the Death Notes and start using them in various ways, which leads to a complex web of power struggles and moral dilemmas.
It focuses on the story of L's early days and how he solves cases. In this novel, we see L's unique detective methods and his battle of wits against various criminals.
The theme of sacrifice also exists. L is aware of the risks he takes in dealing with the power of the Death Note and is willing to sacrifice his own safety for the greater good. And there's the exploration of human nature when faced with such a powerful and dangerous tool as the Death Note.
Obviously, L is a very important character. He is a super - intelligent detective with unique quirks. His deductive skills are second to none, and he is constantly on the hunt for the truth regarding the Death Note. Then there's Near, another highly intelligent individual who is also involved in the events related to the Death Note.
One of the main themes is the battle between good and evil. Light, with the Death Note, represents a form of extreme justice that blurs the line between right and wrong. Another theme is the power of intelligence. Light and L constantly outwit each other using their brilliant minds. Also, it touches on the concept of morality. The use of the Death Note to kill people, even criminals, raises questions about who has the right to judge and take lives.