In the film, a few changes were made to the character. At the film's beginning, Light is a first-year law student at a university, instead of still being in high school as in the beginning of the manga and anime. Light's motives differ; in this version, he uses the Death Note out of frustration from the perceived failures of the Japanese justice system. Light, prior to his discovery of the Death Note, hacks into the government database and finds that the government secretly acknowledges that it is unable to prosecute many criminals. Light discovers the Death Note in an alley during a rainy night after encountering Takuo Shibuimaru in a club and throwing a law book into the rain in a fit of rage. Light meets Ryuk after killing Shibuimaru. Light has a girlfriend, Shiori Akino, who attends his university. Light kills her at the end of the first movie by controlling someone to murder her then commit suicide, to gain sympathy from the investigation team so he would be allowed to join them.
As in the manga, Light relinquishes ownership of the Death Note in order to prove his innocence. He gives the notebook to Kiyomi Takada. After Takada is caught, Light kills her to recover the Death Note. L states that he will test the 13-Day Rule. Rem, knowing that this will reveal Misa's identity as the 2nd Kira, writes both L's and Watari's names in the Death Note. Light then proceeds to write his father's name in the book, manipulating his father to return the confiscated Death Note.
Light confronts his father, but Soichiro does not die. The investigation team members, including L, reveal themselves. Having already written his own name in the Death Note, thus negating Rem's actions, L tells Light that he had just written in a fake note.
Light tries to write on a hidden piece of Death Note, but Matsuda shoots him. Light tells Ryuk to write the team's names, promising to show him many interesting things, and begins to laugh. He stops, however, when Ryuk shows him that he had written just one name: Light's. Light tries to stop Ryuk, but merely passes right through him. As Light begins to succumb to the effects of the Death Note, Ryuk takes this opportunity to reveal to him that humans that have used the Death Note are barred from entering either Heaven or Hell, instead spending eternity in nothingness. Light dies in his father's arms, begging him to believe that he acted as Kira to put the justice, which Soichiro had taught him since his childhood, into practice. The film concludes one year later, on Light's birthday. Sayu fetches Soichiro and says that Kira helped reduce crime rates, however, she says that she does not support Kira as Light was killed by Kira (which is what Soichiro told her). Light is portrayed by Tatsuya Fujiwara, known for his role as Shuya Nanahara in Battle Royale.
Kenichi Matsuyama, the actor who played L in the film series, said that Light and L are "extremely" alike in that they have "a very strong sense of justice".[25]