Yuki Shien

Yuki Shien (紫苑優輝, Shien Yuuki) is a main character exclusive to the Death Note live-action film series. As a devoted Kira supporter, he uses his computer hacking skills to track down the six Death Notes in both Death Note: New Generation and Death Note: Light Up the NEW World.

History
Shien's family was murdered when he was young, but Shien survived the attack. Following his family's death, he was raised in an orphanage. Kira killed his family's murderer, and Shien became devoted to Kira. After Kira disappeared, Shien searched for him and became a cyber-terrorist to help the world.

Plot
In 2016, in the second episode of Death Note: New Generation, Shien finds Kanatomo Karin's video where she is controlled by a Death Note. Karin's last words are an anagram for "Kira, I have it too," and Shien hacks her laptop. He remotely turns on the webcam while Ryuzaki is in Karin's room investigating her murder. J notices that the camera has been turned on, giving Ryuzaki enough warning to put his mask on so Shien is unable to see his face.

The third episode focuses on Shien's history and his decision to use the Death Note. One day, a Death Note drops into his room. Shien chooses two criminals who murdered a family and were freed ten years earlier: Kazutoshi Namaki and Taichi Kunugida. He looks into them, and he personally confronts Kunugida before killing him.

In the film Death Note: Light Up the NEW World, Shien continues searching for the other Death Notes.