Biography

L Lawliet was born October 31st, 1979. There is little evidence that he had a family, residing in Wammy's House (an orphanage founded by Watari; L's close assistant). He was 179 centimeters (5'10") tall and wieghed 50 kilograms (110 lbs). His blood type is still unkonwn.
He tended to second-guess everything he was presented with, and was extremely meticulous and analytical. He had several quirks that made him who he was, such as preferring to crouch rather than sit, eating only sweet foods like desserts and fruits, and holding items very delicately. L stayed in England for five years, and during that time he was the champion in tennis for the England Junior Cup.
L was the greatest detective in the world. The second-best and third best detectives (Eraldo Coil  Deneuve) were also L under different aliases. He helped police solve numerous crimes and was investigating the Kira case when he died.

Courtesy of Wikipedia