I am L; I was a former resident of Wammy's House, one of Watari's orphanages, as well as a safe haven and educational facility specifically for intellectually-gifted children. Therefore, similar to Near and Mello, my abilities were discovered while living there, and I am an orphan. I use the aliases Hideki Ryuga , Ryuzaki, Eraldo Coil , and Deneuve , the latter two for which I have developed reputation as the second- and third-best detectives in the world, I am quite secretive and only communicate with the world through my assistant Watari. I never show my face to the world, instead representing myself with a capital L in Old English Five or cloister black. After meeting the Kira investigation team, I request that the task force refer to me as Ryuzaki for discretion. The Kira investigation team never learned my true name.

My disheveled and languid appearance masks my great powers of deduction and insight. I tend to second-guess everything I am presented with, and I am extremely meticulous and analytical. I have several quirks such as preferring to crouch rather than sit, eating only sweet foods like desserts and fruits, and holding items very delicately. I stayed in England for five years, and during that time I was the champion in tennis for the England Junior Cup. I also secretly assume the identities of the world's second and third best detectives, (Eraldo Coil and Deneuve respectively).

I suspect early in the investigation that Light Yagami is Kira, but can not obtain any concrete evidence. In several situations, Light seems to be proven innocent by the circumstances, but I remain skeptical. If Light were Kira, the case would be solved, and I have trouble letting go of this simple and complete solution. I can easily present my conclusion publicly at any time, and with my reputation, taken seriously. When Light discovers my "Hideki Ryuga" alias Light reasons that if he writes this name in the Death Note, the face of the pop idol could pop into Light's mind and therefore Light would inadvertently kill the pop idol; this would increase suspicion on Light.

Because of my initial suspicions of Light, I decided to join To-Oh University, the university that Light attends, using the name of Hideki Ryuga for investigative purposes. I attend To-Oh because I feel confidence in my reasoning skills and wishes to test them. I also intend to tell Light that he can "take the offensive." I understand that my act is dangerous and since I understand Light's thought process I feel confident that Light will not kill my at this point.

After I introduce myself as Ryuga, Light does not attempt to kill me since the name is conspicuously fake. Also, he has no way to know at the time whether the person is the real L or a proxy acting under orders. Light also reasons that L would have already introduced himself to Light's father earlier, and thus that if he somehow killed L, he would be easily uncovered as Kira. Light also fears that if he writes Hideki Ryuga into the Death Note, that the face of the pop singer from which the alias was derived would enter Light's head, and Hideki Ryuga would die by accident, which would lead L to the obvious conclusion that Light is Kira.

Whenever I give percentages to indicate how much he suspects a person of committing a crime, such as "five percent," in reality I mean over 90 percent. Although I give Light a low percentage indicating how much I suspect Light, in reality I am "pretty certain" that Light is Kira.