L, who also uses the aliases Hideki Ryuga, Ryuzaki, Eraldo Coil and Deneuve, the latter two for which he has developed reputations as the second—and third—best detectives in the world, is quite secretive and only communicates with the world through his assistant Watari. He never shows his face to the world, instead of representing himself with a capital L in Cloister Black font. After meeting the Kira investigation team, he requests that the task force refers to him as Ryuzaki for discretion. The Kira investigation team never learns his true name. L's disheveled and languid appearance masks his great powers of deduction and insight. He tends to second-guess everything he is presented with and is extremely meticulous and analytical. He has several quirks such as preferring to crouch rather than sit, eating only sweet foods like desserts and fruits, and holding items very delicately. He stayed in England for five years, and during that time he was the champion in tennis for the England Junior Cup. L suggests that even though he eats only sweet foods, he remains underweight because the brain uses the most calories of any organ in the body. He also says that if he sits normally, his reasoning ability would drop 40%. (Source: Wikipedia, Death Note Profiles)

Age (during the series): 17-23 Light, born on February 28, 1986, is a third-year high school student (12th grade) at Daikoku Private Academy (大国学園, Daikoku Gakuen) who also attends supplemental classes at Gamou Prep Academy at the beginning of the story. Light has a father, Soichiro Yagami, who is the head of the Police Force. Light also has a mother, Sachiko Yagami, and a younger sister, Sayu Yagami. In Spring 2004, Light becomes a first-year student (freshman) at To-Oh University (東応大学, Tōō Daigaku), becoming one of two freshman representatives; L is the other freshman representative. During a tennis game with L at To-Oh, spectators reveal that Light was the junior high school tennis champion in 1999 and 2000. After his 2000 victory, Light quit tennis as he entered high school. Yagami Light is a brilliant college student. Nicknamed "Kira," he uses the Death Note to create his ideal world of justice under him, its new God. Though he looks frail, Light is an extremely athletic person, with an aptitude to find an opponent's weak point. He is a genius, which adds to his notion that only he is fit to judge humanity and steer it on a proper moral course.