Albeit it is never explicitly stated, it is safe to assume that Light never killed anyone before finding the Death Note. With this in mind there are two options to consider what happened after Light began to use it: was it the Death Note which, in a way or another, caused Light to become Kira, or did Light always had the desire, and above all the will, to kill criminals in order to save the world? In other words…what was the Death Note for Light? A tool which allowed him to make his dream come true or a tool which turned his good intentions to arrest criminals into killing them1?
Let’s trace step by step what happened shortly before and after Ryuk’s Death Note was dropped in the human world.
First Contact
At the beginning of Death Note, Light and Ryuk are shown in their worlds. Both are very bored and think that their world is rotten2. While Light is still at school, he notices a notebook falling on the ground. When the lessons are over, he it picks up the notebook and begins to read the instructions on how to use it. Initially he thinks it is all a bad joke and even after reading all the rules, he is convinced that the notebook is nothing less than a well-made prank.
Light: This is so twisted. Why do people like these kind of things? It’s immature as bad luck letters. [volume 1, chapter 1, page 13]
At this point the manga flashes forward five days, five days during which Light’s ideas on the Death Note completely changes. After meeting Ryuk, Light explains that the notebook had the power to make Light use it at least once so we are shown what happened during those crucial days.
- It must be remembered that even before owning the Death Note, Light had worked with the police and helped them to solve various cases. [↩]
- In the anime there is an additional scene before Light expresses his thoughts. On his way home several news reports about crimes are played in the background, probably to hint at the reason that will bring Light to use the Death Note. [↩]


